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Background & Aims Increased prevalence of obesity is paralleled by an increase in non-alcoholic steatohepatitis ( NASH). We previously found that the expression of ADAMTS5 (A Disintegrin And Metalloproteinase with Thrombospondin type 1 motifs; member 5) is enhanced in expanding adipose tissue. However, no information is available on a potential role in liver pathology. We studied the effect of ADAMTS5 deficiency on NASH in mice. Methods Wild-type ( Adamts5+/+) and deficient ( Adamts5−/−) mice were kept on a standard- or high-fat diet ( HFD) for 15 weeks. Alternatively, steatohepatitis was induced with methionine/choline-deficient ( MCD) diet. Results HFD feeding resulted in comparable body weights for both genotypes, but Adamts5−/− mice had approximately 40% lower liver weight ( P = 0.0004). In the Adamts5−/− mice, the HFD as well as the MCD diet consistently induced less NASH with less fibrosis. The deteriorating effect of ADAMTS5 on the liver during diet-induced obesity may be due, at least in part, to proteolytic cleavage of the matrix components syndecan-1 and versican, thereby enhancing hepatic triglyceride clearance from the circulation. Plasma lipid levels were elevated in obese Adamts5−/− mice. There was no clear effect of ADAMTS5 deficiency on glycaemia or glucose tolerance, whereas insulin sensitivity was somewhat improved. Furthermore, Adamts5−/− mice were protected from hepatic mitochondrial dysfunction, as indicated by increased mitochondrial respiratory chain complex activity, higher ATP levels and higher expression of antioxidant enzymes. Conclusions Absence of ADAMTS5 preserves liver integrity in a diet-induced obesity model. Selective targeting of ADAMTS5 could provide a new therapeutic strategy for treatment/prevention of NASH. [ABSTRACT FROM AUTHOR]

Abstract: Background: Different serologic tests are available for the diagnosis of celiac disease (CD). Aim: To evaluate the diagnostic performance of anti-tissue transglutaminase (tTG) and anti-deamidated gliadin (DGP) for the serologic diagnosis of CD. Methods: The study population consisted of 107 consecutive adult CD and 542 consecutive disease controls who underwent an intestinal biopsy. Samples were tested for total IgA, IgA anti-tTG, and IgG anti-DGP antibodies using assays from 2 manufacturers (INOVA and Thermo Fisher). Samples were also tested by a screening assay that simultaneously detects IgA and IgG antibodies to tTG and DGP (tTG/DGP screen) (INOVA). Results: Positivity for anti-DGP or anti-tTG had a likelihood ratio for CD that varied between 20 and 115, depending on the assay. Double positivity (positive for anti-tTG and anti-DGP) had the highest likelihood ratio (≥215) for CD. The likelihood ratios for single positivity (positivity for one assay combined with negativity for the other) had a likelihood ratio between 0.8 and 10.1. The likelihood ratio for CD was lowest (≤0.12) for double negative test results. Decision tree analysis revealed that determining IgA anti-tTG and IgG anti-DGP in all patients performed better than other serologic strategies. Conclusions: The use of likelihood ratios improves the clinical interpretation of serologic testing for CD. Double positive test results had the highest likelihood ratio for CD, whereas double negative test results had the lowest likelihood ratio. [Copyright &y& Elsevier]

Abstract: Background: We investigated whether taking into account IgA anti-tissue transglutaminase antibody concentration (IgA anti-tTG) and total IgA concentration could improve clinical interpretation of serologic testing for celiac disease (CD). Methods: We retrospectively identified 43 consecutive newly diagnosed CD patients and 545 consecutive disease control patients who had an IgA anti-tTG request during the 42-month study period and for whom intestinal biopsy results were available. Results: Sensitivity and specificity of the IgA anti-tTG assay from Genesis was 95.3% and 92.7%, respectively, with a likelihood ratio (LR) of 12.4. The LR for CD markedly increased with increasing IgA anti-tTG concentration (from 2.0 for results between 7 and 20U/ml up to 319 for results >100U/ml). The LR for CD was also higher in patients with a normal IgA concentration (0.82–4.53g/L) compared to patients with an increased IgA concentration (15.3 vs. 3.1, respectively). These observations were confirmed with a second IgA anti-tTG assay from BioRad. Conclusion: Sensitivity of IgA anti-tTG was good. Specificity, however, was reduced when IgA anti-tTG was weak positive or when the IgA concentration was increased. Taking into account IgA anti-tTG concentration and IgA concentration improves clinical interpretation of serologic testing for CD. [Copyright &y& Elsevier]

Abstract: Background: We examined whether the use of test result interval-specific likelihood ratios (LR) could improve the clinical interpretation of serum FLC κ/λ ratio for the diagnosis of malignant plasma cell disorders. Methods: We calculated LRs for different FLC κ/λ intervals using sera from patients diagnosed with intact multiple myeloma (MM), light chain MM (LCMM), non-secretory MM (NSMM) and light chain amyloidosis (AL-A). Consecutive patients with a clinical suspicion of a monoclonal B-cell disorder that were diagnosed with MGUS or no B-cell monoclonal disorder served as the disease control group. Results: Using LRs for different test result intervals, a distinction can be made between FLC κ/λ ratios that are within the normal diagnostic range, ratios that are inconclusive (1.66–5.0, LR±1), ratios that indicate the possible presence of a malignant plasma cell disorder (0.05–0.25 and >5.0–10, LR±10) and ratios that were suggestive of a malignant plasma cell disorder (<0.05 or >10; LR±50). A FLC κ/λ ratio within the normal diagnostic range virtually excluded LCMM and AL-A, but not intact MM or NSMM. Conclusions: Interpreting serum FLC κ/λ ratios using LRs for different result intervals improves the clinical interpretation for the diagnosis of malignant plasma cell disorders excluding plasmacytoma. [Copyright &y& Elsevier]

The present study aimed to determine the diagnostic performance of different testing strategies to diagnose malignant B-cell disorder or monoclonal gammopathy of unknown significance (MGUS). Sensitivity and specificity were determined in 833 consecutive patients investigated for a monoclonal gammopathy. Serum protein electrophoresis (PE), serum κ/ λ free light chain (FLC) ratio, and serum and urine immunofixation electrophoresis (IFE) were performed in all patients. Twenty-eight patients were diagnosed with a malignant plasma cell disorder, 25 with B-cell non-Hodgkin lymphoma and 156 with MGUS. Serum PE (with follow-up IFE) plus FLC had a sensitivity of 82·3% and a specificity of 96·8% and missed one plasmacytoma and 23 patients with MGUS. Serum IFE plus urine IFE had a sensitivity of 92·3% and a specificity of 100% and missed two MGUS patients. Serum IFE plus FLC had a sensitivity of 93·8% and a specificity of 96·8% and missed one MGUS patient. Serum PE plus FLC had a significantly lower sensitivity than serum IFE plus FLC or serum IFE plus urine IFE for the diagnosis of MGUS. The sensitivity of serum IFE plus FLC was comparable to the sensitivity of serum IFE plus urine IFE. The specificity of serum IFE plus FLC, however, was lower than the specificity of serum IFE plus urine IFE. [ABSTRACT FROM AUTHOR]

Abstract: Background: Anti-neutrophil cytoplasmic antibodies (ANCA) are associated with primary small vessel vasculitis (SVV). Proteinase-3 (PR3)-ANCA are primarily associated with Wegener granulomatosis, whereas myeloperoxidase (MPO)-ANCA are primarily associated with microscopic polyangiitis (MPA) and vasculitic Churg–Strauss syndrome. We evaluated whether a strategy that is based on screening with ELISA or fluoroenzymeimmunoassay (FEIA) is an accurate alternative to screening with indirect immunofluorescence (IIF). Methods: C-ANCA and P-ANCA were determined by IIF and PR3-ANCA and MPO-ANCA were determined by ELISA (Inova) or FEIA (Phadia) on 326 patients (38 with newly diagnosed SVV and 288 diseased controls). Results: Specificity and positive likelihood ratios were higher for ELISA and FEIA than for IIF. Post-test probability for SVV of a positive test result was higher for ELISA and FEIA than for IIF. Decision tree analysis in which several testing strategies were compared revealed that a testing strategy that is based on screening with ELISA or FEIA had an expected clinical utility that was comparable to screening with IIF and confirming with ELISA or FEIA. The highest expected clinical utility was found when both IIF and ELISA or FEIA were performed on all samples. Conclusions: A strategy based on screening for ANCA with ELISA or FEIA (without prior IIF) is a valuable alternative to screening with IIF and confirming with ELISA or FEIA. [Copyright &y& Elsevier]

Abstract: Cryoglobulins are often estimated by determining cryocrit or total protein content in the cryoprecipitate, but these are only indirect measures. Direct quantification of immunoglobulins in combination with agarose gel electrophoresis, to appreciate the presence of other proteins in the cryoprecipitate, offers a more sensitive and specific tool for confirming the diagnosis of cryoglobulinemia. Using such strategy, we established reference values for immunoglobulins in cryoprecipitate in diseased controls and applied them to 214 consecutive patients. The 97.5th percentile for IgA, IgG and IgM in diseased controls was 2, 11 and 26 mg/L serum, respectively. The distribution of the 49 positive patients (23%) was 10% type I, 33% type IIa, 16% type IIb, and 41% type III. Complement C4 was decreased in 61% and 55% of the patients classified as type II and type III compared to 16% of the patients that were negative for cryoglobulins and 9% of the diseased controls. [Copyright &y& Elsevier]

Abstract: Objective: To evaluate whether taking into account anti-deamidated gliadin peptide (DGP) antibody concentrations improves clinical interpretation. Design and methods: We calculated likelihood ratios (LR) using data from two previously published studies for assays from EUROIMMUN and INOVA. Results: LRs markedly increased with increasing IgG anti-DGP concentrations. LRs also increased with increasing IgA anti-DGP concentrations, although they were lower than for IgG anti-DGP. Conclusions: Use of LRs for different test result intervals improves clinical interpretation. [Copyright &y& Elsevier]

Abstract: Our aim was to evaluate the performance of the commercial Immunetics C6 Lyme ELISA assay as a screening assay for anti-Borrelia burgdorferi antibodies in cerebrospinal fluid (CSF). Sensitivity of C6 ELISA was determined in 28 consecutive patients who were diagnosed with neuroborreliosis and had evidence for intrathecal antibody synthesis on immunoblot analysis. The presence of additional bands in CSF or of bands with a stronger intensity in CSF compared with serum was considered evidence of intrathecal synthesis. All 28 patients tested borderline or positive with C6 ELISA on serum. Of the 28 CSF samples, 17 (61%) and 19 (68%) tested positive with C6 ELISA using a threshold of 0.9 and 0.5 (optical density/cutoff). The C6 Lyme ELISA tested has a low sensitivity for antibody detection in cerebrospinal fluid compared with immunoblot analysis. [Copyright &y& Elsevier]

Early diagnosis of ethylene glycol poisoning is crucial in order to prevent morbidity and mortality. However, diagnosis can sometimes be delayed because of the false elevation of lactate in some chemistry analyzers as a result of the interference of glycolate, a metabolite of ethylene glycol. We present a case of ethylene glycol poisoning presenting with a falsely elevated lactate level on a blood gas analyzer in the emergency department. Given the fact that nowadays there is a marked increase in use of point-of-care analyzers, one should be aware of possible false readings since they use different methods of measuring compared with clinical chemistry analyzers. On the other hand, measuring a “lactate gap” using two different technologies, only one of which is sensitive to glycolate, could be a clinically efficient way to make the diagnosis of advanced ethylene glycol poisoning in the emergency department or other critical care setting. [ABSTRACT FROM AUTHOR]

The article presents a study on the approaches used in reporting diagnostic accuracy. The researchers developed a 3-item questionnaire in which clinicians were asked to estimate the posttest probability and provided diagnostic accuracy information which was presented in terms of sensitivity and specificity, likelihood ratio (LR), or graphically. It says that 81% of clinicians overestimated the probability of disease when diagnostic accuracy was presented as sensitivity and specificity.

Introduction: Severe hyperkalaemia is a serious medical condition requiring immediate medical attention. Before medical treatment is started, pseudohyperkalaemia has to be ruled out. Case description: A 10-month old infant presented to the emergency department with fever and coughing since 1 week. Routine venous blood testing revealed a severe hyperkalaemia of 6.9 mmol/L without any indication of haemolysis. Reanalysis of the plasma sample confirmed the hyperkalaemia (7.1 mmol/L). Based on these results, the clinical pathologist suggested to perform a venous blood gas analysis and electrocardiogram (ECG) which revealed a normal potassium of 3.7 mmol/L and normal ECG, ruling out a potentially life-treating hyperkalaemia. The child was diagnosed with pneumonia. The paediatrician had difficulty to perform the first venous blood collection due to excessive movement of the infant during venipuncture. The muscle contractions of the child in combination with venous stasis most probably led to a local increase of potassium in the sampled limbs. The second sample collected under optimal preanalytical circumstances had a normal potassium. Since muscle contraction typically does not cause severe hyperkalaemia, other causes of pseudohyperkalaemia were excluded. K3-EDTA contamination and familial hyperkalaemia were ruled out and the patient did not have extreme leucocytosis or thrombocytosis. By exclusion a diagnosis of pseudohyperkalaemia due to intense muscle movement and venous stasis was made. Conclusion: This case suggests that intense muscle contraction and venous stasis can cause severe pseudohyperkalemia without hemolysis. Once true hyperkalemia has been ruled out, a laboratory work-up can help identify the cause of pseudohyperkalaemia. [ABSTRACT FROM AUTHOR]

The aim was to determine the antibody response against SARS-CoV-2 spike protein and nucleoprotein using four automated immunoassays and three ELISAs for the detection of total Ig antibodies (Roche) or IgG (Abbott, Diasorin, Snibe, Euroimmun, Mikrogen) in COVID-19 patients. Sensitivity and dynamic trend to seropositivity were evaluated in 233 samples from 114 patients with moderate, severe or critical COVID-19 confirmed with PCR on nasopharyngeal swab. Specificity was evaluated in 113 samples collected before January 2020, including 24 samples from patients with non-SARS coronavirus infection. Sensitivity for all assays was 100% (95% confidence interval 83.7–100) 3 weeks after onset of symptoms. Specificity varied between 94.7% (88.7–97.8) and 100% (96.1–100). Calculated at the cut-offs that corresponded to a specificity of 95% and 97.5%, Roche had the highest sensitivity (85.0% (79.8–89.0) and 81.1% (76.6–85.7), p < 0.05 except vs. Abbott). Seroconversion occurred on average 2 days earlier for Roche total Ig anti-N and the three IgG anti-N assays (Abbott, Mikrogen, Euroimmun) than for the two IgG anti-S assays (Diasorin, Euroimmun) (≥50% seroconversion day 9–10 vs. day 11–12 and p < 0.05 for percent seropositive patients day 9–10 to 17–18). There was no significant difference in the IgG antibody time to seroconversion between critical and non-critical patients. Seroconversion occurred within 3 weeks after onset of symptoms with all assays and on average 2 days earlier for assays detecting IgG or total Ig anti-N than for IgG anti-S. The specificity of assays detecting anti-N was comparable to anti-S and excellent in a challenging control population. [ABSTRACT FROM AUTHOR]

The clinical presentation of celiac disease (CD) varies between children. The objective of this study was to document the pre-test probability for CD based on symptoms and routine laboratory test and to evaluate the performance of two IgA anti-tissue transglutaminase (tTG) assays. We critically reviewed the concept of using multiples of the manufacturer's upper limit of normal (ULN), as proposed in the ESPGHAN guidelines (if IgA tTG is >10 times ULN, no biopsy is needed). The retrospective study included 91 children with newly diagnosed CD and 605 controls (<16 years). All underwent upper endoscopy with small bowel biopsies. Four laboratory parameters and 16 symptoms were registered. All patients were tested for IgA anti-tTG antibodies with assays from Inova Diagnostics and Thermo Fisher Scientific. Some combinations of clinical symptoms and laboratory parameters had a high pre-test probability for CD, such as (combinations of) anorexia, failure to thrive, low ferritin level and elevated AST. The diagnostic performance of both IgA anti-tTG assays was excellent and comparable (no difference in ROC curve area under the curve). At a threshold that corresponds to a specificity of 100% (5 times ULN for Inova Diagnostics and 2 times ULN for Thermo Fisher), the sensitivity was 82% for both assays. At the 10 times ULN threshold, the sensitivity differed between the assays (77% vs. 57%), indicating that such threshold does not completely align interpretation across companies. Our study showed that some combinations of symptoms and aberrant laboratory parameters had a high pre-test probability. The use of the ESPGHAN non-biopsy approach could reduce small bowel biopsies, but thresholds for IgA-tTG levels are not aligned across assays and should be based on predefined likelihood ratios or specificity. [ABSTRACT FROM AUTHOR]