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Background: A population-based reference interval (RI) of thyroid hormones in pregnancy using a standardized methodology is crucial for clinicians to make accurate diagnoses and important for the comparison of test results obtained from different analytic platforms. Methods: We enrolled 600 healthy Chinese women to obtain longitudinal serum samples across gestation, after exclusion of subjects with antibodies to thyroid peroxidase, thyroglobulin or thyrotropin receptor. Gestational age-specific RIs were constructed by using polynomial regression equations with MLwiN. Results: Free thyroxine (fT4) levels rose to a peak at the 7th-8th gestational weeks and then declined gradually till 28th week, while thyrotropin (TSH) level decreased from early pregnancy to a nadir at the 9th week. The data support the recent notion by the American Thyroid Association to raise the TSH upper RI to 4.0 mIU/L. We also demonstrate that thyroid hormone reference ranges are not affected in a mildly iodine-deficient population and by including women with the presence of antibodies against thyroid peroxidase and thyroglobulin who are otherwise healthy. Conclusions: The study highlights a methodology in constructing gestational age-specific thyroid function test RIs on different analytic platforms to provide a better interpretation and comparison of results obtained across different platforms.

Background Eltrombopag is a thrombopoietin receptor agonist used for the treatment of thrombocytopenic conditions. It can cause pH-dependent discoloration of plasma/serum. Eltrombopag is potentially hepatotoxic. It can affect the assessment of hyperbilirubinemia because of its (i) absorbance at ~450 nm (bilirubin), (ii) absorbance at ~550 nm (diazo-bilirubin) and (iii) it can cause yellowish discoloration of the eyes at normal circulating bilirubin levels. Methods We collected 66 samples from patients on a range of eltrombopag dosages up to 150 mg daily. Bilirubin was measured using multiple routine spectrophotometric analyzers, the Doumas reference method and high-performance liquid chromatography (HPLC). Plasma/serum eltrombopag concentrations were determined using liquid chromatography tandem mass spectrometry (LC-MS/MS). Spike-in and admixture experiments delineated the effects of eltrombopag and its metabolites. Results Forty-nine of 52 samples from patients on ≥50 mg daily eltrombopag therapy showed significantly discrepant inter-analyzer total bilirubin results, a difference up to 64 μmol/L (3.7 mg/dL). In one sample, total bilirubin varied from 8 to 65 μmol/L (0.4–3.8 mg/dL) by different routine analyzers, with direct bilirubin ≤4 μmol/L (0.2 mg/dL). There was a positive correlation between total bilirubin difference and plasma eltrombopag concentration (r = 0.679), and spike-in experiments demonstrated that Beckman AU and Doumas reference methods were susceptible to positive interference. HPLC can quantify bilirubin after separating eltrombopag, and results suggest different analyzers are affected to varying degrees by eltrombopag and its metabolites. Conclusions Eltrombopag and its metabolites can cause positive interference to the spectrophotometric measurements of total bilirubin. Accurate measurements of total bilirubin may improve our understanding of the prevalence of hyperbilirubinemia in patients on eltrombopag therapy.

Background: Myocardial injury after noncardiac surgery (MINS) was defined as prognostically relevant myocardial injury due to ischemia that occurs during or within 30 days after noncardiac surgery. The study’s four objectives were to determine the diagnostic criteria, characteristics, predictors, and 30-day outcomes of MINS. Methods: In this international, prospective cohort study of 15,065 patients aged 45 yr or older who underwent in-patient noncardiac surgery, troponin T was measured during the first 3 postoperative days. Patients with a troponin T level of 0.04 ng/ml or greater (elevated “abnormal” laboratory threshold) were assessed for ischemic features (i.e., ischemic symptoms and electrocardiography findings). Patients adjudicated as having a nonischemic troponin elevation (e.g., sepsis) were excluded. To establish diagnostic criteria for MINS, the authors used Cox regression analyses in which the dependent variable was 30-day mortality (260 deaths) and independent variables included preoperative variables, perioperative complications, and potential MINS diagnostic criteria. Results: An elevated troponin after noncardiac surgery, irrespective of the presence of an ischemic feature, independently predicted 30-day mortality. Therefore, the authors’ diagnostic criterion for MINS was a peak troponin T level of 0.03 ng/ml or greater judged due to myocardial ischemia. MINS was an independent predictor of 30-day mortality (adjusted hazard ratio, 3.87; 95% CI, 2.96–5.08) and had the highest population-attributable risk (34.0%, 95% CI, 26.6–41.5) of the perioperative complications. Twelve hundred patients (8.0%) suffered MINS, and 58.2% of these patients would not have fulfilled the universal definition of myocardial infarction. Only 15.8% of patients with MINS experienced an ischemic symptom. Conclusion: Among adults undergoing noncardiac surgery, MINS is common and associated with substantial mortality.

Background: Ethnic differences necessitate a need for local reference intervals (RI), but establishing these can be challenging in some cultures that are reluctant to donate blood. Frozen sera are an alternative, but results can be questionable. Between 1998 and 2001, we collected blood samples from 343 healthy pregnant Chinese women (5–41 weeks' gestation), and in 2001 published gestational RI for thyrotropin thyroid stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3) using the ACS180, now obsolete. As a pilot to re-establishing RI, TSH, FT4 and FT3 were re-assayed in archived specimens using contemporary assays. Methods: Thirty archived specimens (–80°C) with ACS180 TSH concentrations ranging from 0.25 to 3.7 mIU/L were measured using the Roche E170, Advia Centaur and Architect i2000 TSH, FT4 and FT3 assays, along with 10 newer contemporary samples. Results were compared to the original, and examined in context of past and present methodological performances in an external quality assurance (EQA) program. Results: All contemporary assays detected significantly lower TSH and increased FT4 and FT3 concentrations in the stored samples. Conclusions: With reference to methodological performances in EQA, the results obtained with contemporary assays suggest analyte deterioration in specimens and thus their unsuitability for re-establishing RI. Clin Chem Lab Med 2010;48:409–12.

IL-23-dependent IL-17-producing T helper (Th) lymphocytes are associated with autoimmunity. We investigated the immunopathological mechanisms for activation of Th17 cells of patients with systemic lupus erythematosus (SLE). Concentration of cytokines/chemokine in plasma and culture supernatant from SLE patients and healthy controls were measured by ELISA or flow cytometry. Plasma IL-12, IL-17, IL-23 and CXCL10 concentrations and the number of Th17 cells were significantly elevated in SLE patients than control subjects (both p

Objective. The costimulatory interactions of the B7 family molecules CD80 and CD86 on antigen-presenting cells with their T-cell counter-receptors CD28 and CTLA-4 modulate T lymphocyte-mediated immune responses in a reciprocal manner. We investigated the possible aberrant production of soluble (s) forms of the T-cell costimulatory molecules CD80, CD86, CD28 and CTLA-4 in plasma of patients with systemic lupus erythematosus (SLE), an autoimmune disease arising from T-lymphocyte dysregulation. Methods. Plasma concentration and ex vivo production of soluble costimulatory molecules of 79 SLE patients with or without active disease and 40 sex- and age-matched healthy subjects were measured by enzyme-linked immunosorbent assay. Results. Plasma sCTLA-4, sCD28, sCD80 and sCD86 concentrations of all SLE patients were significantly higher than concentrations in control subjects (all P

Monitoring of Epstein–Barr virus (EBV) DNA load in the circulation is clinically valuable for the management of EBV-associated diseases, including nasopharyngeal carcinoma (NPC) and certain lymphomas (1)(2). Many studies have used lymphocytes or peripheral blood mononuclear cells as materials for EBV DNA detection in such patients (3)(4)(5)(6). However, cell-free EBV DNA has also been reported in the plasma and serum of patients with NPC and certain lymphoid malignancies (1)(7). These reports raise fundamental questions on whether EBV DNA exists predominantly in a cellular or cell-free form in the peripheral blood of such patients and whether the relative distribution of these forms of EBV DNA differs in different types of EBV-associated disorders. To study these issues, it is important to ensure that the EBV DNA present in the plasma is truly acellular and that the isolated cellular EBV DNA is free from contamination from the cell-free form that may be present in the plasma. Previous reports on cell-associated EBV DNA have not addressed the impact of the thoroughness of the washing of the isolated circulating cells during sample processing. The first objective of the current study was to investigate the efficiencies of different peripheral blood cell (PBC) clean-up procedures in producing data that would truly reflect the concentration of the cell-associated form of EBV DNA. We then studied the relative distribution profiles of cell-free and cell-associated EBV DNA in blood samples from patients with NPC and lymphoid malignancies. For this study, we recruited 49 patients with NPC and 14 patients with Hodgkin disease, natural killer (NK)/T-cell lymphoma, or Burkitt lymphoma managed at the Department of Clinical Oncology at the Prince of Wales Hospital, Hong Kong. Patients gave informed consent, and ethics approval was received from the Institutional Review Board. EDTA blood …

SUMMARY Severe acute respiratory syndrome (SARS) is a recently emerged infectious disease caused by a novel coronavirus, but its immunopathological mechanisms have not yet been fully elucidated. We investigated changes in plasma T helper (Th) cell cytokines, inflammatory cytokines and chemokines in 20 patients diagnosed with SARS. Cytokine profile of SARS patients showed marked elevation of Th1 cytokine interferon (IFN)-γ, inflammatory cytokines interleukin (IL)-1, IL-6 and IL-12 for at least 2 weeks after disease onset, but there was no significant elevation of inflammatory cytokine tumour necrosis factor (TNF)-α, anti-inflammatory cytokine IL-10, Th1 cytokine IL-2 and Th2 cytokine IL-4. The chemokine profile demonstrated significant elevation of neutrophil chemokine IL-8, monocyte chemoattractant protein-1 (MCP-1), and Th1 chemokine IFN-γ-inducible protein-10 (IP-10). Corticosteroid reduced significantly IL-8, MCP-1 and IP-10 concentrations from 5 to 8 days after treatment (all P

In a 1993 survey, allergic rhinitis was identified as the most common allergic disease in Hong Kong, affecting 29.1% of schoolchildren. Recently (1995), the International Study of Asthma and Allergies in Childhood (ISAAC) also reported 44.5% current rhinitis among Hong Kong teenagers. Our objective was to study the aetiology of allergic rhinitis in Hong Kong using serological tests of allergen sensitization. In 57 allergic rhinitis patients and in the same number of age- and sex-matched controls the following were measured: serum total IgE, mixed aeroallergen IgE (Phadiatop™) and specific IgE versus house dust mite (HDM), cockroach, cat and dog dander, mould mixture (Penicillium, Cladosporium, Aspergillus and Alternaria species) and four local pollens (Bermuda grass, Timothy, ragweed and mugwort). Compared with controls, allergic rhinitis patients (26 males, 31 females; mean (± SD) age 25 ±11 years) had a significantly elevated serum total IgE concentration (mean ± SEM: 496 ± 88 vs 179 ± 38 kU/L) and an increased proportion of positive Phadiatop (95 vs 33%) and specific IgE tests versus HDM (90 vs 44%) and cockroach (42 vs 9%; Mann-Whitney U-test and χ2 tests all P < 0.005). There was no significant difference in sensitization to other allergens tested. House dust mite and cockroach are ubiquitous in Hong Kong with a warm, humid climate and crowded living conditions. Their identification as aetiological agents of allergic rhinitis should help in the development of environmental strategies for reducing the inhalant allergen load to prevent and control this prevalent and costly health problem in our community.

Background: Roche Diagnostics has issued new c-fas calibrators for its automated systems. These produce creatinine values that are more comparable with those obtained by high-performance liquid chromatography. However, this results in an underestimation of measured creatinine at concentrations below 155 μmol/L and an overestimation at concentrations above this value. Methods: Serum and urine creatinine concentrations were prospectively determined on samples from 60 patients using the new (compensated) and old (uncompensated) c-fas calibrators, and Passing-Bablok regression analysis was performed. The regression equations thus determined were then used retrospectively to determine the compensated creatinine results (i.e. those results that would have been obtained using the new calibrator) in those serum and urine samples analysed in the previous year using the old uncompensated c-fas calibrator. The compensated creatinine results were then used to estimate the glomerular filtration rate (GFR) by calculating creatinine clearance. This was done by using the formula: UV/Pt, in which U represents the urinary creatinine concentration (μmol/L), V the urinary collection volume (mL), P the serum creatinine concentration (μmol/L) and t the urinary collection time (min). It was also calculated using the abbreviated Modification of Diet in Renal Disease study group (MDRD) formula. Results: The creatinine clearance as determined using either the UV/Pt calculation or the MDRD formula overestimated GFR by ~30% and ~50%, respectively, in normal individuals with a serum creatinine concentration below 155 μmol/L. However, in patients with mild to moderate renal failure (serum creatinine from 155 to 500 μmol/L), changes in creatinine clearances determined by the two procedures were minimal. Conclusion: When laboratories introduce this new, compensated calibrator into practice, it may be appropriate to discuss its potential impact with clinical staff who monitor patients using creatinine clearance.

Objectives To determine the proportion of noncardiac surgery patients exceeding the published 99th percentile or change criteria with the high sensitivity Troponin T (hs-TnT) assay. Design and methods We measured hs-TnT preoperatively and postoperatively on days 1, 2 and 3 in 325 adults. Results Postoperatively 45% (95% CI: 39–50%) of patients had hs-TnT ≥ 14 ng/L and 22% (95% CI:17–26%) had an elevation (≥ 14 ng/L) and change (> 85%) in hs-TnT. Conclusion Further research is needed to inform the optimal hs-TnT threshold and change in this setting.

Background Circulating bacterial DNA fragment is related to systemic inflammatory state in peritoneal dialysis (PD) patients. We hypothesize that plasma bacterial DNA level predicts cardiovascular events in new PD patients. Methods We measured plasma bacterial DNA level in 191 new PD patients, who were then followed for at least a year for the development of cardiovascular event, hospitalization, and patient survival. Results The average age was 59.3 ± 11.8 years; plasma bacterial DNA level 34.9 ± 1.5 cycles; average follow up 23.2 ± 9.7 months. At 24 months, the event-free survival was 86.1%, 69.8%, 55.4% and 30.8% for plasma bacterial DNA level quartiles I, II, III and IV, respectively (p < 0.0001). After adjusting for confounders, plasma bacterial DNA level, baseline residual renal function and malnutrition-inflammation score were independent predictors of composite cardiovascular end-point; each doubling in plasma bacterial DNA level confers a 26.9% (95% confidence interval, 13.0 – 42.5%) excess in risk. Plasma bacterial DNA also correlated with the number of hospital admission (r = -0.379, p < 0.0001) and duration of hospitalization for cardiovascular reasons (r = -0.386, p < 0.0001). Plasma bacterial DNA level did not correlate with baseline arterial pulse wave velocity (PWV), but with the change in carotid-radial PWV in one year (r = -0.238, p = 0.005). Conclusions Circulating bacterial DNA fragment level is a strong predictor of cardiovascular event, need of hospitalization, as well as the progressive change in arterial stiffness in new PD patients.

Summary Aim We investigated the effect of massive doses of corticosteroid therapy on bone metabolism using specific biochemical markers of bone metabolism, and the prevalence of osteonecrosis in severe acute respiratory syndrome (SARS) patients at a university teaching hospital in Hong Kong. Methods Seventy-one patients with a clinical diagnosis of SARS were studied according to the modified World Health Organization case definition of SARS who were involved in the SARS epidemic between 10 March and 20 June 2003. The clinical diagnosis was confirmed by serological test and/ or molecular analysis. Biochemical markers of bone metabolism were analysed retrospectively using serial clotted blood samples collected from each patient during the course of hospital admission to discharge and subsequent follow-up at out-patient clinic using the arbitrary time periods: (i) Day 90 after the onset of fever. Magnetic resonance imaging of the knee and hip joints were performed post-admission to evaluate the prevalence of osteonecrosis amongst these SARS patients. Various risk factors for the development of osteonecrosis were assessed using receiver operating characteristics curve comparison with appropriate test statistics and Spearman’s coefficients of rank correlation with biochemical bone markers. Results Biochemical markers of bone metabolism showed significant bone resorption as evidenced by a marked increase in serum C-terminal telopeptide concentration (CTx) from Day 28-44 after the onset of fever. With tapering down of corticosteroid dosage, CTx started to return to previous baseline level from Day 51 onwards, while other bone formation markers, serum osteocalcin and bone- specific alkaline phosphatase concentrations (OC and BALP, respectively), started to increase. The latter effect was even more marked after Day >90. Seven patients developed radiological evidence of osteonecrosis. The prevalence of osteonecrosis in this cohort was 9.9%. A total corticosteroid dosage of >1900mg hydrocortisone, >2000 mg methylprednisolone, >13 340 mg hydrocortisone-equivalent corticosteroid therapy, and >18 days on corticosteroid therapy were found to be significant risk factors for the subsequent development of osteonecrosis. There were also significant positive correlations amongst various biochemical bone markers in this patient cohort. Conclusion Both bone resorption and formation markers were unable to predict the subsequent development of osteonecrosis. The use of high dose of hydrocortisone or methylprednisolone for an extended duration was shown to be a significant risk factor for osteonecrosis. Its prevalence in this cohort is comparable to those reported in the literature for SARS patients with high-dose corticosteroid therapy. The Day 28–44 increase in the serum CTx coincided with the timing of corticosteroid use. The Day >51 increase in serum OC and BALP coincided with the timing of corticosteroid withdrawal.

Background. Osteopontin (OPN) is an extracellular matrix cell adhesion phosphoprotein with immunological activities including stimulation of macrophage chemotaxis, T-helper type 1 lymphocyte response and B-cell antibody synthesis. Overexpression of OPN has been associated with the development of the autoimmune/lymphoproliferative syndrome. Methods. We measured the plasma concentration and ex vivo production of OPN, and the plasma proinflammatory IL-18 concentration in 54 SLE patients with or without renal impairment (RSLE group and SLE group, respectively) and 26 sex- and age-matched control (NC) subjects using an enzyme-linked immunoabsorbent assay. Results. Plasma OPN concentrations were significantly higher in RSLE and SLE patients than in the NC group (both P

The discovery of circulating fetal nucleic acid in maternal plasma has opened up new possibilities for noninvasive prenatal diagnosis. Thus far, a gender- and polymorphism-independent fetal-specific target that can be used for prenatal screening and monitoring in all pregnant women has not been reported. In addition, the origin of such circulating nucleic acid has remained unclear. Here we provide direct evidence that the placenta is an important source of fetal nucleic acid release into maternal plasma by demonstrating that mRNA transcripts from placenta-expressed genes are readily detectable in maternal plasma. The surprising stability of such placental mRNA species in maternal plasma and their rapid clearance after delivery demonstrate that such circulating mRNA molecules are practical markers for clinical use. The measurement of such plasma mRNA markers has provided a gender-independent approach for noninvasive prenatal gene expression profiling and has opened up numerous research and diagnostic possibilities.

Aim The importance of establishing reliable reference intervals for local populations cannot be overemphasised. The reference intervals of analytes obtained from literature and manufacturers may not apply to our serving population due to differences in subject ethnicity and assay principle. The objective of this study was to set up reference intervals of common serum analytes for local Hong Kong Chinese. Methods Healthy local Chinese blood donors were recruited and blood specimens were obtained after questionnaire screening and consent. Samples were processed and analysed by Beckman Coulter UniCel Chemistry Analyzers. Reference limits were subsequently defined by statistical methods. Results Data from 803 subjects were analysed. The reference intervals of 21 analytes were generally similar to those provided by the assay manufacturer. However, we found higher upper reference limits for creatine kinase and lower potassium reference limits in our group, which might be due to genuine ethnic difference, lifestyle and blood collection procedure variations. Conclusion Reference intervals of common serum analytes have been set up for the local Chinese population. Some of them are not in accordance with those documented in the literature or Manufacturer’s Insert. Clinicians can make use of our results for quality patient care and management in our population.