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Background Fecal immunochemical tests (FITs) are widely used for colorectal cancer (CRC) screening; however, high ambient temperatures were found to reduce test accuracy. More recently, proprietary globin stabilizers were added to FIT sample buffers to prevent temperature-associated hemoglobin (Hb) degradation, but their effectiveness remains uncertain. We aimed to determine the impact of high temperature (>30°C) on OC-Sensor FIT Hb concentration with current FITs, characterize FIT temperatures during mail transit, and determine impact of ambient temperature on FIT Hb concentration using data from a CRC screening program. Methods FITs were analyzed for Hb concentration after in vitro incubation at different temperatures. Data loggers packaged alongside FITs measured temperatures during mail transit. Separately, screening program participants completed and mailed FITs to the laboratory for Hb analysis. Regression analyses compared the impact of environmental variables on FIT temperatures and separately on FIT sample Hb concentration. Results In vitro incubation at 30 to 35°C reduced FIT Hb concentration after >4 days. During mail transit, maximum FIT temperature averaged 6.4°C above maximum ambient temperature, but exposure to temperature above 30°C was for less than 24 hours. Screening program data showed no association between FIT Hb concentration and maximum ambient temperatures. Conclusions Although FIT samples are exposed to elevated temperatures during mail transit, this is brief and does not significantly reduce FIT Hb concentration. These data support continuation of CRC screening during warm weather with modern FITs with a stabilizing agent when mail delivery is ≤4 days.

Background The use of quantitative human chorionic gonadotropin (hCG) as a tumor marker is widely accepted despite lack of FDA-approval for oncology. Differences in iso- and glycoform recognition among hCG immunoassays is well established, exhibiting wide inter-method variability. Here, we assess the utility of 5 quantitative hCG immunoassays for use as tumor markers in trophoblastic and non-trophoblastic disease. Methods Remnant specimens were obtained from 150 patients with gestational trophoblastic disease (GTD), germ cell tumors (GCT), or other malignancies. Specimens were identified by review of results from physician-ordered hCG and tumor marker testing. Five analyzer platforms were used for split specimen analysis of hCG: Abbott Architect Total, Roche cobas STAT, Roche cobas Total, Siemens Dimension Vista Total, and Beckman Access Total. Results Frequency of elevated hCG concentrations (above reference cutoffs) was highest in GTD (100%), followed by GCT (55% to 57%), and other malignancies (8% to 23%). Overall, the Roche cobas Total detected elevated hCG in the greatest number of specimens (63/150). Detection of elevated hCG in trophoblastic disease was nearly equivalent among all immunoassays (range, 41 to 42/60). Conclusions While no immunoassay is likely to be perfect in all clinical situations, results for the 5 hCG immunoassays evaluated suggest that all are adequate for use of hCG as a tumor marker in gestational trophoblastic disease and select germ cell tumors. Further harmonization of hCG methods is needed as serial testing for biochemical tumor monitoring must still be performed using a single method. Additional studies are needed to assess the utility of quantitative hCG as a tumor marker in other malignant disease.

Background Serum free light chain (sFLC) assays are interpreted using a sFLC-ratio-based reference interval (manufacturer’s interval) that was defined using a cohort of healthy patients. However, renal impairment elevates the sFLC-ratio, leading to a high false positive rate when using the manufacturer’s interval. Prior studies have developed renal-specific reference intervals; however, this approach has not been widely adopted due to practical limitations. Thus, there remains a critical need for a renally robust sFLC interpretation method. Methods Retrospective data mining was used to define patient cohorts that reflect the spectrum of renal function seen in clinical practice. Two new reference intervals, one based on the sFLC-ratio and one based on a novel principal component analysis (PCA)-based metric, were developed for the FREELITE assay (Binding Site) on the Roche Cobas c501 instrument (Roche). Results Compared to the manufacturer’s reference interval, both new methods exhibited significantly lower false positive rates and greater robustness to renal function while maintaining equivalent sensitivity for monoclonal gammopathy (MG) diagnosis. While not significantly different, the point estimate for sensitivity was highest for the PCA-based approach. Conclusion Renally robust sFLC interpretation using a single reference interval is possible given a reference cohort that reflects the variation in renal function observed in practice. Further studies are needed to achieve sufficient power and determine if the novel PCA-based metric offers superior sensitivity for MG diagnosis. These new methods offer the practical advantages of not requiring an estimated glomerular filtration rate result or multiple reference intervals, thereby lowering practical barriers to implementation.

Background Mitochondria are cytosolic organelles within most eukaryotic cells. Mitochondria generate the majority of cellular energy in the form of adenosine triphosphate (ATP) through oxidative phosphorylation (OxPhos). Pathogenic variants in mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) lead to defects in OxPhos and physiological malfunctions (Nat Rev Dis Primer 2016;2:16080.). Patients with primary mitochondrial disorders (PMD) experience heterogeneous symptoms, typically in multiple organ systems, depending on the tissues affected by mitochondrial dysfunction. Because of this heterogeneity, clinical diagnosis is challenging (Annu Rev Genomics Hum Genet 2017;18:257–75.). Laboratory diagnosis of mitochondrial disease depends on a multipronged analysis that can include biochemical, histopathologic, and genetic testing. Each of these modalities has complementary strengths and limitations in diagnostic utility. Content The primary focus of this review is on diagnosis and testing strategies for primary mitochondrial diseases. We review tissue samples utilized for testing, metabolic signatures, histologic findings, and molecular testing approaches. We conclude with future perspectives on mitochondrial testing. Summary This review offers an overview of the current biochemical, histologic, and genetic approaches available for mitochondrial testing. For each we review their diagnostic utility including complementary strengths and weaknesses. We identify gaps in current testing and possible future avenues for test development.

Background Our study addressed the diagnostic performance of the Atellica® IM High-Sensitivity Troponin I (hs-cTnI) assay for the rapid rule-out of myocardial infarction (MI) using a single hs-cTnI measurement at presentation in patients presenting to a US emergency department (ED). Methods This was a prospective, observational, cohort study of consecutive ED patients with suspected acute coronary syndrome, using 12-lead electrocardiogram and serial hs-cTnI measurements ordered on clinical indication (SAFETY, NCT04280926). ST-segment elevation MI patients were excluded. The optimal threshold required a sensitivity ≥99% and a negative predictive value (NPV) ≥99.5% for MI during index hospitalization as primary outcome. Type 1 MI (T1MI), myocardial injury, and 30-day adverse events were considered secondary outcomes. Event adjudications were established using the hs-cTnI assay used in clinical care. Results In 1171 patients, MI occurred in 97 patients (8.3%), 78.3% of which were type 2 MI. The optimal rule out hs-cTnI threshold was Conclusions A single hs-cTnI measurement strategy enabled the rapid identification of patients at low risk of MI and 30-day adverse events, allowing potential discharge early after ED presentation. Clinicaltrials.gov Registration number NCT04280926.

Background Biallelic deletions at 15q15.3, including STRC and CATSPER2, cause autosomal recessive deafness-infertility syndrome (DIS), while biallelic deletions of STRC alone cause nonsyndromic hearing loss. These deletions are among the leading genetic causes of mild–moderate hearing loss, but their detection using chromosomal microarray (CMA) is impeded by a tandem duplication containing highly homologous pseudogenes. We sought to assess copy number variant (CNV) detection in this region by a commonly-employed CMA platform. Methods Twenty-two specimens with known 15q15.3 CNVs, determined by droplet digital PCR (ddPCR), were analyzed by CMA. To investigate the impact of pseudogene homology on CMA performance, a probe-level analysis of homology was performed, and log2 ratios of unique and pseudogene-homologous probes compared. Results Assessment of 15q15.3 CNVs by CMA compared to ddPCR revealed 40.9% concordance, with frequent mis-assignment of zygosity by the CMA automated calling software. Probe-level analysis of pseudogene homology suggested that probes with high homology contributed to this discordance, with significant differences in log2 ratios between unique and pseudogene-homologous CMA probes. Two clusters containing several unique probes could reliably detect CNVs involving STRC and CATSPER2, despite the noise of surrounding probes, discriminating between homozygous vs heterozygous losses and complex rearrangements. CNV detection by these probe clusters showed 100% concordance with ddPCR. Conclusions Manual analysis of clusters containing unique CMA probes without significant pseudogene homology improves CNV detection and zygosity assignment in the highly homologous DIS region. Incorporation of this method into CMA analysis and reporting processes can improve DIS diagnosis and carrier detection.

Background Lipids play a central role in the pathogenesis of cardiovascular disease (CVD), a leading cause of morbidity and mortality worldwide. Plasma lipids and lipoproteins are routinely measured to help identify individuals at high risk of developing CVD and to monitor patients’ response to therapy. The landscape of lipid testing is rapidly changing, including new ways to estimate traditional lipid parameters (e.g., low-density lipoprotein-cholesterol [LDL-C] calculations) and new lipid parameters that show superiority for risk prediction (e.g., non-high-density lipoprotein-cholesterol [non-HDL-C], apolipoprotein B [apoB], and lipoprotein a [Lp(a)]). Content Various national guidelines for managing dyslipidemia to prevent CVD are available, which primarily focus on LDL-C for identifying those at high risk and setting thresholds for optimal response to therapy. However, LDL-C can be calculated and measured in various ways, each with advantages and disadvantages. Importantly, the recently established Sampson–NIH LDL-C equation appears to be superior to preceding calculations, as is clear from the literature and in guidelines. There is now a shift towards using lipid parameters other than LDL-C, such as non-HDL-C, apoB, and Lp(a), to identify high-risk patients and/or establish treatment targets. Summary The goal of this review is to discuss the present and future of lipid testing for CVD risk assessment through describing various national clinical guidelines, critically reviewing methods to calculate and measure LDL-C and discussing the clinical utility of additional lipid parameters.

Background Acute chest pain is associated with an increased risk of death and cardiovascular events even when acute myocardial infarction (AMI) has been excluded. Growth differentiation factor-15 (GDF-15) is a strong prognostic marker in patients with acute chest pain and AMI, but the prognostic value in patients without AMI is uncertain. This study sought to investigate the ability of GDF-15 to predict long-term prognosis in patients presenting with acute chest pain without AMI. Methods In total, 1320 patients admitted with acute chest pain without AMI were followed for a median of 1523 days (range: 4 to 2208 days). The primary end point was all-cause mortality. Secondary end points included cardiovascular (CV) death, future AMI, heart failure hospitalization, and new-onset atrial fibrillation (AF). Results Higher concentrations of GDF-15 were associated with increased risk of death from all causes (median concentration in non-survivors vs survivors: 2124 pg/mL vs 852 pg/mL, P < 0.001), and all secondary end points. By multivariable Cox regression, GDF-15 concentration ≥4th quartile (compared to Conclusions Higher concentrations of GDF-15 were associated with increased risk of mortality from all causes and risk of future CV events.

Background Dysregulation of calcium ion homeostasis in neurons is well documented in Alzheimer disease (AD), and high plasma calcium concentrations have been associated with cognitive decline in the elderly; however, a potential causal nature for this association has not been elucidated. Methods Plasma calcium ion concentrations of 97 968 individuals from the Copenhagen General Population Study (CGPS) were included and multifactorial Cox regressions using splines or quartiles was performed to investigate the observational association. A plasma calcium ion genome-wide association study (GWAS) was performed in 2 independent subgroups of the CGPS. The plasma calcium ion GWAS and publicly available genomic data sets for plasma total calcium and AD were used to perform the currently most powerful 2-sample Mendelian randomization studies. Results The hazard ratio for lowest vs highest quartile of the calcium ion concentration was 1.24 (95% CI, 1.08–1.43) for AD. The plasma calcium ion GWAS identified 3 independent loci. None of the genetic instruments for plasma concentrations of calcium ions or total calcium were associated with AD risk. Conclusions High plasma concentrations of calcium ions were observationally associated with increased risk of AD but genetic associations were not found, suggesting that the observational findings may be due to reverse causation or residual confounding.

Background Exposure to heavy metals is common as a result of environmental contamination of air, water, and soil as well as accumulation in food, tobacco, herbal medicines, and occupational contact. However, clinically relevant toxicity is much less prevalent. Toxic effects, when they occur, may present with non-specific symptoms, resulting in a very large differential for clinicians to consider. Content Arsenic, cadmium, lead, and mercury are four heavy metals with no biological role in humans. However, these metals are commonly used in industrial applications and consumer products. Since these elements are not biodegradeable, their potential toxic effects may be long-lasting within the environment. These heavy metals have the potential to accumulate in vital organs such as the brain, heart, and kidney where they may disrupt normal cellular functioning and if exposures are repetitive or of high concentration, toxicity may result. Summary The objective of this review is to provide an overview of arsenic, cadmium, lead, and mercury physical properties, common sources of exposure, basic toxicokinetics and health effects, and to review clinical guidelines and treatment strategies. Acute and chronic symptoms and recommended laboratory biomarker testing are also discussed.

Background Current guidelines recommend 0/1 h algorithms using high-sensitivity cardiac troponin (hs-cTn) for fast diagnosis of myocardial infarction (MI). Yet, for some assays, existing data is limited. We aimed to evaluate the diagnostic performance and the prognostic value of a rapid 0/1 h algorithm for the Access hs-cTnI assay. Methods In consecutive patients presenting with suspected MI, we measured concentrations of Access hs-cTnI at presentation and after 1 hour. Final diagnosis was adjudicated independently by 2 cardiologists. Parameters for diagnostic performance were calculated, applying the recently derived European Society of Cardiology (ESC) 0/1 h algorithm for Access hs-cTnI. Additionally, we assessed the prognostic utility of Access hs-cTnI for the composite end point of all-cause mortality and incident MI at 3 years. Results In 1879 patients, 257 non-ST-elevation MIs occurred. Application of the 0/1 h algorithm classified 44.5% as rule-out, 20.3% as rule-in, and triaged 35.1% to the observe group. High rule-out safety was confirmed with a sensitivity of 97.7% (95% CI, 95.0%–99.1%) and a negative predictive value of 99.3% (95% CI, 98.4%–99.7%). Rule-in capacity was moderate with a specificity of 88.0% (95% CI, 86.3%–89.6%) and a positive predictive value of 50.8% (95% CI, 45.7%–55.9%). After exclusion of patients with ST-elevation MI the results showed strong prognostic value, even after adjustment for cardiovascular risk factors and comorbidities, with adjusted hazard ratios of 2.51 (95% CI, 1.56–4.04) in the observe and 3.55 (95% CI, 2.18–5.79) in the rule-in group for the composite end point of all-cause mortality and incident MI at 3 years, compared to ruled-out patients. Conclusion The ESC 0/1 h algorithm for Access hs-cTnI allows safe and efficient triage of patients with suspected MI and has strong prognostic utility up to 3 years after the initial evaluation.

Background Currently, no authoritative guidelines exist recommending the analytical performance specification (APS) of blood beta-hydroxybutyrate (BOHB) testing in order to meet the clinical needs of patients. This study has applied existing diabetic ketoacidosis (DKA) BOHB diagnostic thresholds and the recommended rates of fall in BOHB concentrations during DKA treatment to establish pragmatic APSs for BOHB testing. Methods Required analytical performance was based on 2 clinical requirements: (a) to reliably distinguish between non-adjacent DKA BOHB diagnostic categories of 0 mmol/L decline). Results An analytical coefficient of variation (CV) of 99% certainty, assuming zero bias. In contrast, within-day CVs of 4.9%, 7.0%, and 9.1% at 3 mmol/L BOHB were required to assure truly falling ketone concentrations with 99% (optimal), 95% (desirable), and 90% (minimal) probability, respectively. These CVs are larger at lower BOHB concentrations and smaller at higher concentrations. Conclusions Reliable tracking of changes in BOHB during DKA treatment largely drives the requirement for analytical performance. These data can be used to guide minimal, desirable, and optimal performance targets for BOHB meters and laboratory assays.

Background Classical homocystinuria (HCU) results from deficient cystathionine β-synthase activity, causing elevated levels of Met and homocysteine (Hcy). Newborn screening (NBS) aims to identify HCU in pre-symptomatic newborns by assessing Met concentrations in first-tier screening. However, unlike Hcy, Met testing leads to a high number of false-positive and -negative results. Therefore, screening for Hcy directly in first-tier screening would be a better biomarker for use in NBS. Methods Dried blood spot (DBS) quality control and residual clinical specimens were used in analyses. Several reducing and maleimide reagents were investigated to aid in quantification of total Hcy (tHcy). The assay which was developed and validated was performed by flow injection analysis–tandem mass spectrometry (FIA-MS/MS). Results Interferents of tHcy measurement were identified, so selective derivatization of Hcy was employed. Using N-ethylmaleimide (NEM) to selectively derivatize Hcy allowed interferent-free quantification of tHcy by FIA-MS/MS in first-tier NBS. The combination of tris(2-carboxyethyl)phosphine (TCEP) and NEM yielded significantly less matrix effects compared to dithiothreitol (DTT) and NEM. Analysis of clinical specimens demonstrated that the method could distinguish between HCU-positive, presumptive normal newborns, and newborns receiving total parenteral nutrition. Conclusions Here we present the first known validated method capable of screening tHcy in DBS during FIA-MS/S first-tier NBS.

Background Plasma glial fibrillary acidic protein (GFAP) has emerged as a promising biomarker in neurological disorders, but further evidence is required in relation to its usefulness for diagnosis and prediction of Alzheimer disease (AD). Methods Plasma GFAP was measured in participants with AD, non-AD neurodegenerative disorders, and controls. Its diagnostic and predictive value were analyzed alone or combined with other indicators. Results A total of 818 participants were recruited (210 followed). Plasma GFAP was significantly higher in AD than in non-AD dementia and non-demented individuals. It increased in a stepwise pattern from preclinical AD, through prodromal AD to AD dementia. It effectively distinguished AD from controls [area under the curve (AUC) > 0.97] and non-AD dementia (AUC > 0.80) and distinguished preclinical (AUC > 0.89) and prodromal AD (AUC > 0.85) from Aβ-normal controls. Adjusted or combined with other indicators, higher levels of plasma GFAP displayed predictive value for risk of AD progression (adjusted hazard radio= 4.49, 95%CI, 1.18–16.97, P = 0.027 based on the comparison of those above vs below average at baseline) and cognitive decline (standard-β=0.34, P = 0.002). Additionally, it strongly correlated with AD-related cerebrospinal fluid (CSF)/neuroimaging markers. Conclusions Plasma GFAP effectively distinguished AD dementia from multiple neurodegenerative diseases, gradually increased across the AD continuum, predicted the individual risk of AD progression, and strongly correlated with AD CSF/neuroimaging biomarkers. Plasma GFAP could serve as both a diagnostic and predictive biomarker for AD.

Background Hematological parameters have many applications in athletes, from monitoring health to uncovering blood doping. This study aimed to deliver biological variation (BV) estimates for 9 hematological parameters by a Biological Variation Data Critical Appraisal Checklist (BIVAC) design in a population of recreational endurance athletes and to assess the effect of self-reported exercise and health-related variables on BV. Methods Samples were drawn from 30 triathletes monthly for 11 months and measured in duplicate for hematological measurands on an Advia 2120 analyzer (Siemens Healthineers). After outlier and homogeneity analysis, within-subject (CVI) and between-subject (CVG) BV estimates were delivered (CV-ANOVA and log-ANOVA, respectively) and a linear mixed model was applied to analyze the effect of exercise and other related variables on the BV estimates. Results CVI estimates ranged from 1.3% (95%CI, 1.2-1.4) for mean corpuscular volume to 23.8% (95%CI, 21.6-26.3) for reticulocytes. Sex differences were observed for platelets and OFF-score. The CVI estimates were higher than those reported for the general population based on meta-analysis of eligible studies in the European Biological Variation Database, but 95%CI overlapped, except for reticulocytes, 23.9% (95%CI, 21.6-26.5) and 9.7% (95%CI, 6.4-11.0), respectively. Factors related to exercise and athletes’ state of health did not appear to influence the BV estimates. Conclusions This is the first BIVAC-compliant study delivering BV estimates that can be applied to athlete populations performing high-level aerobic exercise. CVI estimates of most parameters were similar to the general population and were not influenced by exercise or athletes’ state of health.

Background Myocardial injury after non-cardiac surgery (MINS), based on measurement of troponin T, is associated with perioperative major adverse cardiovascular events (MACE). We therefore determined the high-sensitivity troponin I (hsTnI) thresholds associated with 30 day MACE after non-cardiac surgery. Methods We performed a nested biobank cohort study of 4553 patients from the Vascular Events in Non-Cardiac Surgery Patients Cohort Evaluation (VISION) Study. We measured hsTnI (ADVIA Centaur® hsTnI assay) on postoperative days 1 to 3 in patients ≥45 years undergoing non-cardiac surgery. An iterative Cox proportional hazard model determined peak postoperative hsTnI thresholds independently associated with MACE (i.e., death, myocardial infarction occurring on postoperative day 4 or after, non-fatal cardiac arrest, or congestive heart failure) within 30 days after surgery. Results MACE occurred in 89/4545 (2.0%) patients. Peak hsTnI values of Conclusion A peak postoperative hsTnI ≥75 ng/L was associated with >5-fold increase in the risk of 30 days MACE compared to levels Clinicaltrials.gov Registration Number: NCT00512109.

Background Multiple treatments are available for metastatic castration-resistant prostate cancer (mCRPC), including androgen receptor signaling inhibitors (ARSI) enzalutamide and abiraterone, but therapy resistance remains a major clinical obstacle. We examined the clinical utility of low-pass whole-genome sequencing (LPWGS) of circulating tumor DNA (ctDNA) for prognostication in mCRPC. Methods A total of 200 plasma samples from 143 mCRPC patients collected at the start of first-line ARSI treatment (baseline) and at treatment termination (n = 57, matched) were analyzed by LPWGS (median: 0.50X) to access ctDNA% and copy number alteration (CNA) patterns. The best confirmed prostate specific antigen (PSA) response (≥50% decline [PSA50]), PSA progression-free survival (PFS), and overall survival (OS) were used as endpoints. For external validation, we used plasma LPWGS data from an independent cohort of 70 mCRPC patients receiving first-line ARSI. Results Baseline ctDNA% ranged from ≤3.0% to 73% (median: 6.6%) and CNA burden from 0% to 82% (median: 13.1%) in the discovery cohort. High ctDNA% and high CNA burden at baseline was associated with poor PSA50 response (P = 0.0123/0.0081), poor PFS (P < 0.0001), and poor OS (P < 0.0001). ctDNA% and CNA burden was higher at PSA progression than at baseline in 32.7% and 42.3% of the patients. High ctDNA% and high CNA burden at baseline was also associated with poor PFS and OS (P ≤ 0.0272) in the validation cohort. Conclusions LPWGS of ctDNA provides clinically relevant information about the tumor genome in mCRPC patients. Using LPWGS data, we show that high ctDNA% and CNA burden at baseline is associated with short PFS and OS in 2 independent cohorts.

Background Elevated BNP and the N-terminal fragment of the proBNP (NT-proBNP) are hallmarks of heart failure (HF). Generally, both biomarkers parallel each other. In patients receiving sacubitril/valsartan, BNP remained stable while NT-proBNP decreased. As BNP and NT-proBNP assays have limited specificity due to cross-reactivity, we quantified by mass spectrometry (MS) the contributing molecular species. Methods We included 356 healthy volunteers, 100 patients with acute dyspnoea (49 acute decompensated HF; 51 dyspnoea of non-cardiac origin), and 73 patients with chronic HF and reduced ejection fraction treated with sacubitril/valsartan. BNP and NT-proBNP immunoreactivities (BNPir and NT-proBNPir) were measured by immunoassays (Abbott ARCHITECT and Roche Diagnostics proBNPII) and proBNP-derived peptides and glycosylation at serine 44 by MS on plasma samples. Results BNPir corresponded to the sum of proBNP1–108, BNP1–32, BNP3–32, and BNP5–32 (R2 = 0.9995), while NT-proBNPir corresponded to proBNP1–108 and NT-proBNP1–76 not glycosylated at serine 44 (R2 = 0.992). NT-proBNPir was better correlated (R2 = 0.9597) than BNPir (R2 = 0.7643) with proBNP signal peptide (a surrogate of proBNP production). In patients receiving sacubitril/valsartan, non-glycosylated NT-proBNP1–76 remained constant (P = 0.84) despite an increase in NT-proBNP1–76 and its glycosylation (P < 0.0001). ProBNP1–108 remained constant (P = 0.12) while its glycosylation increased (P < 0.0001), resulting in a decrease in non-glycosylated proBNP1–108 (P < 0.0001), and in NT-proBNPir. Conclusions Glycosylation interfered with NT-proBNPir measurement, explaining the discrepant evolution of these 2 biomarkers in patients receiving sacubitril/valsartan. Both BNPir and NT-proBNPir are surrogates of proBNP1–108 production, NT-proBNPir being more robust in the clinical contexts studied.

Background Somatic copy number alterations (sCNAs) acquired during the evolution of breast cancer provide valuable prognostic and therapeutic information. Here we present a workflow for screening sCNAs using picogram amounts of cell-free DNA (cfDNA) and single circulating tumor cells (CTCs). Methods We repurposed the Ion ReproSeq PGS™ preimplantation genetic testing kit to perform shallow whole genome sequencing on 178 cfDNA samples (300 pg) and individual CTCs from 10 MBC patients with metastatic breast cancer (MBC) recovered by CellSearch®/DEPArray™. Results were analyzed using a tailored ichorCNA workflow. Results sCNAs were detected in cfDNA of 41/105 (39%) patients with MBC and 3/23 (13%) primary breast cancers on follow-up (PBC FU), all of whom subsequently relapsed. In 8 of 10 MBCs, individual CTCs had a higher copy number count than matched cfDNA. The median tumor fraction detected by ichorCNA was 0.34 (range 0.17–0.58) for MBC and 0.36 (range 0.31–0.37) for PBC FU. Patients with detectable tumor fraction (≥ 0.1) and TFx and OncomineTM variants had significantly lower overall survival rates (P values P = 0.002 and P < 0.0001 for the log-rank test, respectively). Conclusions The ReproSeq PGS assay is rapid, at approximately $120 per sample, providing both a sCNA profile and estimation of the tumor DNA fraction from limiting cfDNA template (300pg) and individual CTCs. The approach could be used to examine the copy number landscape over time to guide treatment decisions, support future trial designs, and be applied to low volume blood spot samples enabling remote monitoring.

Background Tumor heterogeneity and lack of personalized prognosis leads to bladder cancer (BlCa) patients’ lifelong surveillance with invasive interventions, highlighting the need for modern minimally invasive tools for disease management. Herein, we have evaluated the clinical utility of preoperative serum cell-free DNA (cfDNA) in ameliorating patients’ risk-stratification and prognosis. Methods cfDNA was purified from 190 preoperative BlCa patients and 26 healthy individuals’ serum samples and quantified by 2 assays: an in-house quantitative real-time PCR (qPCR) assay using LEP as reference control and a direct fluorometric assay using Qubit HS dsDNA. Capillary electrophoresis was performed in 31 samples for cfDNA fragment profiling. Tumor relapse/progression and metastasis/death were used as clinical endpoints for non-muscle-invasive bladder cancer and muscle-invasive bladder cancer (MIBC), respectively. Results cfDNA profiling by capillary electrophoresis highlighted that total and fragment-related cfDNA levels were significantly increased in BlCa and associated with advance disease stages. Evaluation of cfDNA levels by both Qubit/qPCR displayed highly consistent results (rs = 0.960; P < 0.001). Higher cfDNA was correlated with MIBC and stronger risk for early metastasis (Qubit:hazard ratio [HR] = 3.016, P = 0.009; qPCR:HR = 2.918, P = 0.004) and poor survival (Qubit:HR = 1.898, P = 0.042; qPCR:HR = 1.888, P = 0.026) of MIBC patients. Multivariate cfDNA-fitted models led to superior risk stratification and net benefit for MIBC prognosis compared to disease established markers. Conclusions Elevated preoperative cfDNA levels are strongly associated with higher risk for short-term metastasis and poor outcome of MIBC, supporting modern noninvasive disease prognosis and management.

Background The role of sex hormone-binding globulin (SHBG) levels in clinical risk stratification and intervention for coronary heart disease (CHD) remains uncertain. We aimed to examine whether circulating levels of SHBG are predictive of CHD risk in men and women. Methods We investigated the association between SHBG and the risk of incident CHD in 128 322 men and 135 103 women free of CHD at baseline in the prospective United Kingdom Biobank (UKB) cohort. The unconfounded associations were estimated using Mendelian randomization (MR) analysis. We further conducted a meta-analysis to integrate currently available prospective evidence. CHD events included nonfatal and fatal myocardial infarction and coronary revascularization. Results In the UKB, during a median of 11.7 follow-up years, 10 405 men and 4512 women developed CHD. Serum levels of SHBG were monotonically associated with a decreased risk of CHD in both men (adjusted hazard ratio [HR] per log nmol/L increase in SHBG: 0.88 [0.83–0.94]) and women (HR: 0.89 [0.83–0.96]). MR-based analyses suggested causality and a dose-response relationship of SHBG with CHD risk. A cumulative meta-analysis including 216 417 men and 138 282 women from 11 studies showed that higher levels of SHBG were prospectively associated with decreased CHD risk in men comparing the highest with the lowest quartile: pooled relative risk (RR) 0.81 (0.74–0.89) and women (pooled RR: 0.86 [0.78–0.94]). Conclusions Higher circulating SHBG levels were directly and independently predictive of lower CHD risk in both men and women. The utility of SHBG for CHD risk stratification and prediction warrants further study.

Background Isothermal amplification is considered to be one of the most promising tools for point-of-care testing molecular diagnosis. However, its clinical application is severely hindered by nonspecific amplification. Thus, it is important to investigate the exact mechanism of nonspecific amplification and develop a high-specific isothermal amplification assay. Methods Four sets of primer pairs were incubated with Bst DNA polymerase to produce nonspecific amplification. Gel electrophoresis, DNA sequencing, and sequence function analysis were used to investigate the mechanism of nonspecific product generation, which was discovered to be nonspecific tailing and replication slippage mediated tandem repeats generation (NT&RS). Using this knowledge, a novel isothermal amplification technology, bridging primer assisted slippage isothermal amplification (BASIS), was developed. Results During NT&RS, the Bst DNA polymerase triggers nonspecific tailing on the 3′-ends of DNAs, thereby producing sticky-end DNAs over time. The hybridization and extension between these sticky DNAs generate repetitive DNAs, which can trigger self-extension via replication slippage, thereby leading to nonspecific tandem repeats (TRs) generation and nonspecific amplification. Based on the NT&RS, we developed the BASIS assay. The BASIS is carried out by using a well-designed bridging primer, which can form hybrids with primer-based amplicons, thereby generating specific repetitive DNA and triggering specific amplification. The BASIS can detect 10 copies of target DNA, resist interfering DNA disruption, and provide genotyping ability, thereby offering 100% accuracy for type 16 human papillomavirus detection. Conclusion We discovered the mechanism for Bst-mediated nonspecific TRs generation and developed a novel isothermal amplification assay (BASIS), which can detect nucleic acids with high sensitivity and specificity.

BackgroundPlasma fatty acids (FAs) have been associated with cardiovascular disease (CVD) risk. Diet and endogenous metabolism influence the FA profile of the plasma phospholipid (PL) fraction. In the PREDIMED trial, we examined 1-year changes in the FA profile of plasma PL according to a nutritional intervention with Mediterranean diets, either supplemented with extra-virgin olive oil (MedDiet + EVOO) or mixed nuts (MedDiet + nuts), in a high cardiovascular risk population. We also analyzed if 1-year changes in PL FAs were associated with subsequent cardiovascular risk.MethodsWe included 779 participants in our case-cohort study: 185 incident cases and 594 participants in the subcohort (including 31 overlapping cases). The end point was the incidence of CVD. We measured the FAs of plasma PL at baseline and after 1 year of intervention.ResultsMedDiet + EVOO increased C17:0 and C20:3n9 in linear regression models [β coefficientperSD : 0.215 (95% CI, 0.032–0.399) and 0.271 (0.107–0.434), respectively] and decreased 16:1n7 and C22:4n6 [βperSD: −0.239 (95% CI, −0.416 to −0.061) and −0.287 (95% CI, −0.460 to −0.113), respectively] vs the control group. MedDiet + nuts increased C18:3n3 [βperSD: 0.382 (95% CI, 0.225 – 0.539)], C18:2n6 [βper SD: 0.250 (95% CI, 0.073 — 0.428)], C18:0 [βperSD: 0.268 (95% CI, 0.085—0.452)], and C22:0 [βper SD: 0.216 (95% CI, 0.031—0.402)]; and decreased the sum of six n6 FAs [βper SD: −0.147 (95% CI, −0.268 to −0.027)] vs the control group. The 1-year increase in C18:2n6 was inversely associated with the subsequent CVD risk (HRperSD: 0.64 (95% CI, 0.44–0.92)).ConclusionsMedDiet interventions changed n6 FAs and C16:1n7c; other changes were specific for each group: MedDiet + EVOO increased C17:0 and C20:3n9, and MedDiet + Nuts C18:3n3, C18:2n6, C18:0, and C22:0 FAs.

BackgroundThe aim is to evaluate the clinical utility of a long-read sequencing-based approach termed comprehensive analysis of thalassemia alleles (CATSA) in prenatal diagnosis of thalassemia.MethodsA total of 278 fetuses from at-risk pregnancies identified in thalassemia carrier screening by PCR-based methods were recruited from 9 hospitals, and PCR-based methods were employed for prenatal diagnosis. CATSA was performed retrospectively and blindly for all 278 fetuses.ResultsAmong the 278 fetuses, 263 (94.6%) had concordant results and 15 (5.4%) had discordant results between the 2 methods. Of the 15 fetuses, 4 had discordant thalassemia variants within the PCR detection range and 11 had additional variants identified by CATSA. Independent PCR and Sanger sequencing confirmed the CATSA results. In total, CATSA and PCR-based methods correctly detected 206 and 191 fetuses with variants, respectively. Thus, CATSA yielded a 7.9% (15 of 191) increment as compared with PCR-based methods. CATSA also corrected the predicted phenotype in 8 fetuses. Specifically, a PCR-based method showed one fetus had homozygous HBB c.52A > T variants, while CATSA determined the variant was heterozygous, which corrected the predicted phenotype from β-thalassemia major to trait, potentially impacting the pregnancy outcome. CATSA additionally identified α-globin triplicates in 2 fetuses with the heterozygous HBB c.316-197C > T variant, which corrected the predicted phenotype from β-thalassemia trait to intermedia and changed the disease prognosis.ConclusionsCATSA represents a more comprehensive and accurate approach that potentially enables more informed genetic counseling and improved clinical outcomes compared to PCR-based methods.

Equivalent results for the same measurand in clinical samples (CSs), measured using different end-user in-vitro diagnostic medical devices (IVD-MDs), are essential for the application of clinical practice guidelines for diagnosis, treatment, monitoring, or risk assessment. The International Organization for Standardization (ISO) document 17511:2020 specifies how to establish metrological traceability to the highest available reference system component to enable equivalent results among IVD-MDs. Commutability with CSs is an essential property of a reference material used as a calibrator in a calibration hierarchy. However, not all calibrators in a calibration hierarchy are required to be commutable; different calibration hierarchies have different requirements for which calibrators must be commutable with CSs. Because assessment of commutability is a substantial effort, it is therefore important to determine which calibrators need to be commutable when implementing a calibration hierarchy. We provide guidance on which calibrators must be commutable with CSs, when a correction for any noncommutability bias is appropriate, and when commutability of a calibrator with CSs is not required for various types of calibration hierarchies described in ISO 17511:2020.

Background Familial dysbetalipoproteinemia (FDBL) is a monogenic disease due to variants in APOE with a highly variable phenotype. Current diagnostic lipid-based methods have important limitations. The objective is twofold: to define characteristics of dysbetalipoproteinemia (DBL) based on the analysis of APOE in patients from a lipid unit and in a sample from the general population, and to propose a screening algorithm for FDBL. Methods Lipids and APOE genotype from consecutive unrelated subjects from Miguel Servet University Hospital (MSUH) (n 3603), subjects from the general population participants of the Aragon Workers Health Study (AWHS) (n 4981), and selected subjects from external lipid units (Ext) (n 390) were used to define DBL criteria and to train and validate a screening tool. Results Thirty-five subjects from MSUH, 21 subjects from AWHS, and 31 subjects from Ext were APOE2/2 homozygous. The combination of non high-density lipoprotein cholesterol (non-HDLc)/apoB 1.7 plus triglycerides/apoB 1.35, in mg/dL (non-HDLc [mmol/L]/apolipoprotein B (apoB) [g/L] 4.4 and triglycerides [mmol/L]/apoB [g/L] 3.5), provided the best diagnostic performance for the identification of subjects with hyperlipidemia and APOE2/2 genotype (sensitivity 100 in the 3 cohorts, and specificity 92.8 [MSUH], 80.9 [AWHS], and 77.6 [Ext]). This improves the performance of previous algorithms. Similar sensitivity and specificity were observed in APOE2/2 subjects receiving lipid-lowering drugs. Conclusions The combination of non-HDLc/apoB and triglycerides/apoB ratios is a valuable tool to diagnose DBL in patients with hyperlipidemia with or without lipid-lowering drugs. FDBL diagnosis requires DBL and the presence of a compatible APOE genotype. Most adult APOE2/2 subjects express DBL, making FDBL as common as familial hypercholesterolemia in the population.

BackgroundPatients with chronic kidney disease (CKD) have dysfunctional high-density lipoprotein (HDL) particles as compared with the general population. Understanding the lipid composition of HDL may provide mechanistic insight. We tested associations of estimated glomerular filtration rate (eGFR) and albuminuria with relative HDL abundance of ceramides, sphingomyelins, and phosphatidylcholines in participants with CKD.MethodsWe studied 490 participants with CKD from the Seattle Kidney Study. HDL was isolated from plasma; targeted lipidomics was used to quantify the relative abundance of ceramides, sphingomyelins, and phosphatidylcholines per 10 µg of total HDL protein. We evaluated the associations of eGFR and albuminuria with levels of individual lipids and lipid classes (including 7 ceramides, 6 sphingomyelins, and 24 phosphatidylcholines) using multivariable linear regression, controlling for multiple comparisons via the false discovery rate.ResultsThe mean (SD) eGFR was 45 (24) mL/min/1.73 m2; the median (IQR[interquartile range]) albuminuria was 108 (16, 686) mg/g (12.2 [1.8, 77.6] mg/mmol) urine creatinine. After adjusting for demographics, past medical history, laboratory values, and medication use, eGFR was not associated with higher relative abundance of any class of lipids or individual lipids. Greater albuminuria was significantly associated with a higher relative abundance of total ceramides and moderate–long R-chain sphingomyelins, ceramides 22:0 and 24:1, hexosylceramide 16:0, sphingomyelin 16:0, and phosphatidylcholines 29:0, 30:1, and 38:2; the strongest association was for hexosylceramide 16:0 (increase per doubling of urine albumin to creatinine ratio 0.022 (95% CI, 0.012–0.032).ConclusionsGreater albuminuria was significantly associated with specific alterations in the lipid composition of HDL in participants with CKD.

BackgroundElevated concentrations of lipoprotein(a) [Lp(a)] are directly related to an increased risk of cardiovascular diseases, making it a relevant biomarker for clinical risk assessment. However, the lack of global standardization of current Lp(a) measurement procedures (MPs) leads to inconsistent patient care. The International Federation for Clinical Chemistry and Laboratory Medicine working group on quantitating apolipoproteins by mass spectrometry (MS) aims to develop a next-generation SI (International system of units)-traceable reference measurement system consisting of a MS-based, peptide-calibrated reference measurement procedure (RMP) and secondary serum-based reference materials (RMs) certified for their apolipoprotein(a) [apo(a)] content. To reach measurement standardization through this new measurement system, 2 essential requirements need to be fulfilled: a sufficient correlation among the MPs and appropriate commutability of future serum-based RMs.MethodsThe correlation among the candidate RMP (cRMP) and immunoassay-based MPs was assessed by measuring a panel of 39 clinical samples (CS). In addition, the commutability of 14 different candidate RMs was investigated.ResultsResults of the immunoassay-based MPs and the cRMPs demonstrated good linear correlations for the CS but some significant sample-specific differences were also observed. The results of the commutability study show that RMs based on unspiked human serum pools can be commutable with CS, whereas human pools spiked with recombinant apo(a) show different behavior compared to CS.ConclusionsThe results of this study show that unspiked human serum pools are the preferred candidate secondary RMs in the future SI-traceable Lp(a) Reference Measurement System.

The number of testing sites receiving their first Certificate of Waiver (CoW) under the Clinical Laboratory Improvement Amendments of 1988 (CLIA) increased significantly after the start of the COVID-19 pandemic. We compared the first-time CoWs in 2020–2021 to those in 2018–2019. The total number of first-time CoWs during 2020–2021 was more than twice what it was in 2018–2019, corresponding to population testing needs during the COVID-19 pandemic, especially in assisted living facility, pharmacy, physician office, and school/student health service settings. This study highlighted the need to strengthen clinical testing strategies to be better prepared for future public health emergencies.

Background Nuclear-derived cell-free DNA (cfDNA) molecules in blood plasma are nonrandomly fragmented, bearing a wealth of information related to tissues of origin. DNASE1L3 (deoxyribonuclease 1 like 3) is an important player in shaping the fragmentation of nuclear-derived cfDNA molecules, preferentially generating molecules with 5 CC dinucleotide termini (i.e., 5 CC-end motif). However, the fragment end properties of microbial cfDNA and its clinical implication remain to be explored. Methods We performed end motif analysis on microbial cfDNA fragments in plasma samples from patients with sepsis. A sequence context-based normalization method was used to minimize the potential biases for end motif analysis. Results The end motif profiles of microbial cfDNA appeared to resemble that of nuclear cfDNA (Spearman correlation coefficient: 0.82, P value 0.001). The CC-end motif was the most preferred end motif in microbial cfDNA, suggesting that DNASE1L3 might also play a role in the fragmentation of microbe-derived cfDNA in plasma. Of note, differential end motifs were present between microbial cfDNA originating from infection-causing pathogens (enriched at the CC-end) and contaminating microbial DNA potentially derived from reagents or the environment (nearly random). The use of fragment end signatures allowed differentiation between confirmed pathogens and contaminating microbes, with an area under the receiver operating characteristic curve of 0.99. The performance appeared to be superior to conventional analysis based on microbial cfDNA abundance alone. Conclusions The use of fragmentomic features could facilitate the differentiation of underlying contaminating microbes from true pathogens in sepsis. This work demonstrates the potential usefulness of microbial cfDNA fragmentomics in metagenomics analysis.

Background Despite recent large-scale discordance studies showing definitively that atherosclerotic cardiovascular disease (ASCVD) risk correlates better with apolipoprotein B (apoB) than with low-density lipoprotein cholesterol (LDL-C), the latter remains the recommended metric for guiding lipid-lowering treatment decisions in the United States. A major barrier to change, in this regard, is the lack of guideline-recommended apoB treatment targets. We developed a simple method to “translate” apoB values into population-equivalent LDL-C units, allowing apoB-based treatment decisions to be made using LDL-C targets. Methods Sequentially collected, population-based samples underwent standard lipid panel analysis and apoB testing by immunoassay. Those with triglycerides greater than 1000 mg/dl were excluded, leaving a study cohort of 15 153 individuals. Results Linear regression of calculated LDL-C values against percentile-equivalent apoB values yielded an equation to convert apoB into percentile-equivalent LDL-C units: [LDL-C equivalents = 1.38(apoB) – 29] (R2 = 0.999). The extent of discordance between LDL-C and apoB was examined in subgroups with similar LDL-C, ranging from very low (55–70 mg/dL) to very high (175–190 mg/dL). Among individuals with very low LDL-C, 40% had discordantly higher apoB, indicating higher ASCVD risk. Of those with very high LDL-C, 49% had discordantly lower apoB. Across the range, a minority of patients (25%–40%) had concordant levels of apoB, confirming that discordance between these biomarkers is highly prevalent. Similar results were found in discordance analysis between apoB and non-high-density lipoprotein cholesterol (HDL-C). Conclusions Providing visibility to discrepancies among LDL-C, non-HDL-C, and apoB should help to facilitate more rapid and widespread adoption of apoB for managing ASCVD risk.

Background We examined the interplay of apolipoprotein B (apoB) and LDL particle size, approximated by the LDL-cholesterol (LDL-C)/apoB ratio, on the risk of new-onset coronary heart disease (CHD). Methods Participants without cardiovascular disease from the UK Biobank (UKB; n = 308 182), the Women’s Health Study (WHS; n = 26 204), and the Framingham Heart Study (FHS; n = 2839) were included. Multivariable Cox models were used to assess the relationship between apoB and LDL-C/apoB ratio and incidence of CHD (14 994 events). Our analyses were adjusted for age, sex (except WHS), HDL-cholesterol (HDL-C), systolic blood pressure, antihypertensive treatment, diabetes, and smoking. Results In all 3 studies, there was a strong positive correlation between apoB and LDL-C (correlation coefficients r = 0.80 or higher) and a weak inverse correlation of apoB with LDL-C/apoB ratio (−0.28 ≤ r ≤ −0.14). For all 3 cohorts, CHD risk was higher for higher levels of apoB. Upon multivariable adjustment, the association between apoB and new-onset CHD remained robust and statistically significant in all 3 cohorts with hazard ratios per 1 SD (95% CI): 1.24 (1.22–1.27), 1.33 (1.20–1.47), and 1.24 (1.09–1.42) for UKB, WHS, and FHS, respectively. However, the association between LDL-C/apoB and CHD was statistically significant only in the FHS cohort: 0.78 (0.64–0.94). Conclusions Our analysis confirms that apoB is a strong risk factor for CHD. However, given the null association in 2 of the 3 studies, we cannot confirm that cholesterol-depleted LDL particles are substantially more atherogenic than cholesterol-replete particles. These results lend further support to routine measurement of apoB in clinical care.

Background Recent studies using single molecule, real-time (SMRT) sequencing revealed a substantial population of analyzable long cell-free DNA (cfDNA) in plasma. Potential clinical utilities of such long cfDNA in pregnancy and cancer have been demonstrated. However, the performance of different long-read sequencing platforms for the analysis of long cfDNA remains unknown. Methods Size biases of SMRT sequencing by Pacific Biosciences (PacBio) and nanopore sequencing by Oxford Nanopore Technologies (ONT) were evaluated using artificial mixtures of sonicated human and mouse DNA of different sizes. cfDNA from plasma samples of pregnant women at different trimesters, hepatitis B carriers, and patients with hepatocellular carcinoma were sequenced with the 2 platforms. Results Both platforms showed biases to sequence longer (1500 bp vs 200 bp) DNA fragments, with PacBio showing a stronger bias (5-fold overrepresentation of long fragments vs 2-fold in ONT). Percentages of cfDNA fragments 500 bp were around 6-fold higher in PacBio compared with ONT. End motif profiles of cfDNA from PacBio and ONT were similar, yet exhibited platform-dependent patterns. Tissue-of-origin analysis based on single-molecule methylation patterns showed comparable performance on both platforms. Conclusions SMRT sequencing generated data with higher percentages of long cfDNA compared with nanopore sequencing. Yet, a higher number of long cfDNA fragments eligible for the tissue-of-origin analysis could be obtained from nanopore sequencing due to its much higher throughput. When analyzing the size and end motif of cfDNA, one should be aware of the analytical characteristics and possible biases of the sequencing platforms being used.

Background In the last decade, immune checkpoint inhibitors have revolutionized the treatment of metastatic nonsmall cell lung cancer without oncogenic addiction. Currently, programmed death ligand 1 (PD-L1) status, assessed in tissue biopsy samples, is the only test for guiding the prescription of these therapies in clinical practice. However, obtaining tumor tissue from patients with lung cancer is not always feasible and PD-L1 positivity is not a guarantee of immunotherapy efficacy. In this context, liquid biopsy, represented by several circulating biomarkers that reflect the tumor characteristics, is emerging as an interesting alternative approach. Content We describe the main blood biomarkers evaluated in patients with metastatic nonsmall cell lung cancer before/during immune checkpoint inhibitor treatment, with a focus on circulating cell-free DNA, circulating tumor DNA (ctDNA), blood tumor mutational burden, and circulating tumor cells (CTCs). Summary Monitoring of ctDNA and CTCs during immunotherapy may be a promising tool to help clinicians in therapeutic decision-making.

Background A "Watch and Wait” (W&W) approach has become an alternative to surgery for locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (nCRT). Precise prediction of pathological complete response (pCR) will improve patient selection for W&W. We investigated the utility of cell-free DNA (cfDNA) fragmentomics in predicting pCR. Methods We recruited 119 LARC patients and evaluated nCRT response by pCR status and pathological or MRI tumor regression grade (mrTRG). Plasma samples before, during, and after nCRT were applied to deep targeted-panel sequencing, with 103 patients having complete samples. cfDNA fragment and 5′-end motif profiles were used to construct elastic-net logistic regression models to predict non-pCR. Predictive performance was measured by area under the receiver operator characteristic curve (AUC), sensitivity, and specificity. Results In the training cohort, the model based on 5′-end motif profile plus mrTRG achieved the highest cross-validation AUC (0.92, 95% CI, 0.91–0.93). The AUC in a testing cohort was 0.96 (95% CI, 0.90–1.00). The models based on 5′-end motif profile alone or in combination with mrTRG both maintained good predictive ability for patients without detectable circulating tumor DNA (AUC 0.94, 95% CI, 0.93–0.95; AUC 0.95, 95% CI, 0.94–0.96). In an external validation cohort, the model trained with a local 5′-end motif profile obtained an AUC of 0.878 (95% CI, 0.801–0.956) in discriminating colorectal cancer from healthy subjects. Conclusions The combination of a 5′-end motif profile with mrTRG has the potential to predict the response to nCRT, and therefore may improve the patient selection for a W&W approach.

Background Identification of hemoglobin (Hb) variants is of significant value in the clinical diagnosis of hemoglobinopathy. However, conventional methods for identification of Hb variants in clinical laboratories can be inadequate due to the lack of structural characterization. We describe the use of neutral-coating capillary electrophoresis coupled with high-resolution mass spectrometry (CE-HR-MS) to achieve high-performance top-down identification of Hb variants. Methods An Orbitrap Q-Exactive Plus mass spectrometer was coupled with an ECE-001 capillary electrophoresis (CE) unit through an EMASS-II ion source. A PS1 neutral-coating capillary was used for CE. Samples of red blood cells were lysed in water and diluted in 10 mM ammonium formate buffer for analysis. Deconvolution of raw mass spectrometry data was carried out to merge multiple charge states and isotopic peaks of an analyte to obtain its monoisotopic mass. Results The neutral-coating CE could baseline separate individual Hb subunits dissociated from intact Hb forms, and the HR-MS could achieve both intact-protein analysis and top-down analysis of analytes. A number of patient samples that contain Hb subunit variants were analyzed, and the variants were successfully identified using the CE-HR-MS method. Conclusions The CE-HR-MS method has been demonstrated as a useful tool for top-down identification of Hb variants. With the ability to characterize the primary structures of Hb subunits, the CE-HR-MS method has significant advantages to complement or partially replace the conventional methods for the identification of Hb variants.

Objective Hemoglobin Constant Spring (HbCS) is often missed by routine hemoglobin analysis. The aim of this research was to study HbCS stability as identified by capillary electrophoresis (CE) to determine the specimen storage time limit. Methods The EDTA blood of 29 HbCS samples were kept at 4°C and analyzed every workday until CE could not detect HbCS or until 7 weeks after blood collection. The genotypes were confirmed by multiplex polymerase chain reaction. Results The median subject age was 27 years and 10 subjects were male. The HbCS levels were stable during the first 7 days but became undetectable in 5 cases (17.2%) after 1 week. All of them were heterozygous HbCS. Longer detection times were correlated with the higher baseline HbCS levels, with a correlation coefficient of 0.582 (P ≤ 0.001) Conclusion Routine hemoglobin typing and quantitation should be performed within 1 week after blood collection to detect low HbCS levels, especially in heterozygous HbCS.