Explore the vast range of titles available.

Background: A serum ceruloplasmin concentration below 0.20 g/L is conventionally considered as one of the major diagnostic criteria for Wilson disease. This decision threshold has not been fully validated for its diagnostic characteristics, however. In this study, we evaluated various decision thresholds of serum ceruloplasmin concentration in the diagnosis of Wilson disease based on genotype-verified Wilson disease patients, carriers, and normal individuals. Methods: Serum ceruloplasmin concentration was measured by a nephelometric method in 57 Wilson disease patients and 71 family members (49 heterozygotes and 22 wild-type homozygotes), a validation group of 25 subjects clinically suspected of Wilson disease, and 690 normal individuals. We performed ROC analysis using Analyze-it software and confirmed the genotypes by direct DNA sequencing of ATP7B. Results: Serum ceruloplasmin concentrations <0.20, 0.14, and 0.10 g/L showed positive predictive values of 48.3%, 100%, and 100%, respectively, and negative predictive values of 98.7%, 97.1%, and 91.9%. In the validation group, a serum ceruloplasmin threshold of 0.14 g/L rendered 100% sensitivity and specificity. Forty of 690 healthy subjects had serum ceruloplasmin concentrations <0.20 g/L; however, these 40 individuals had normal genotypes by DNA sequencing, and none of the 40 had ceruloplasmin concentrations <0.14 g/L. Conclusions: The diagnostic accuracy for Wilson disease using a serum ceruloplasmin concentration of 0.14 g/L as the local decision threshold was better than that using a threshold of 0.20 g/L. We suggest that laboratories providing ceruloplasmin assays determine decision thresholds based on local populations.

Experiments showed that a single cooked meat meal (225 g boiled beef) can lead to a sharp and transient increase in plasma creatinine, with a peak postprandial increase in adults of 52%, followed by a gradual decrease to baseline after 12 to 24 hours.3 4This phenomenon, also known as ‘goulash effect', may affect clinical interpretation of plasma creatinine level and the estimated glomerular filtration rate.5 6 7 The three paediatric cases described above demonstrated a transient exaggerated increase in creatinine following consumption of homemade meat essence. Pseudo-renal failure secondary to consumption of homemade meat essence resulted in unnecessary hospital admissions, blood taking and imaging studies, as well as a delay in scheduled chemotherapy treatment. Author contributions All authors contributed to the concept or design, acquisition of data, analysis or interpretation of data, drafting of the manuscript, and critical revision of the manuscript for important intellectual content. Ethics approval The study was approved by the Hong Kong Children's Hospital Research Ethics Committee (Ref No.: HKCH-REC-2021-059).

Background Inborn errors of metabolism (IEM) are collectively rare but potentially preventable causes of sudden unexpected death (SUD) in infancy or childhood, and metabolic autopsy serves as the final tool for establishing the diagnosis. We conducted a retrospective review of the metabolic and molecular autopsy on SUD and characterized the biochemical and genetic findings. Methodology A retrospective review of postmortem metabolic investigations (dried blood spot acylcarnitines and amino acid analysis, urine metabolic profiling where available, and next-generation sequencing on a panel of 75 IEM genes) performed for infants and children who presented with SUD between October 2016 and December 2021 with inconclusive autopsy findings or autopsy features suspicious of underlying IEM in our locality was conducted. Clinical and autopsy findings were reviewed for each case. Results A total of 43 infants and children aged between zero days to 10 years at the time of death were referred to the authors' laboratories throughout the study period. One positive case of multiple acyl-CoA dehydrogenase deficiency was diagnosed. Postmortem reference intervals for dried blood spot amino acids and acylcarnitines profile were established based on the results from the remaining patients. Conclusions Our study confirmed the importance of metabolic autopsy and the advantages of incorporating biochemical and genetic testing in this setting.

Pleural fluid adenosine deaminase level can be applied to rapidly detect tuberculous pleural effusion. We aimed to establish a local diagnostic cut-off value for pleural fluid adenosine deaminase to identify patients with tuberculous pleural effusion, and optimise its utility. We retrospectively reviewed the medical records of consecutive adults with pleural fluid adenosine deaminase level measured by the Diazyme commercial kit (Diazyme Laboratories, San Diego [CA], United States) during 1 January to 31 December 2011 in a cluster of public hospitals in Hong Kong. We considered its level alongside early (within 2 weeks) findings in pleural fluid and pleural biopsy, with and without applying Light's criteria in multiple scenarios. For each scenario, we used the receiver operating characteristic curve to identify a diagnostic cut-off value for pleural fluid adenosine deaminase, and estimated its positive and negative predictive values. A total of 860 medical records were reviewed. Pleural effusion was caused by congestive heart failure, chronic renal failure, or hypoalbuminaemia caused by liver or kidney diseases in 246 (28.6%) patients, malignancy in 198 (23.0%), non-tuberculous infection in 168 (19.5%), tuberculous pleural effusion in 157 (18.3%), and miscellaneous causes in 91 (10.6%). All those with tuberculous pleural effusion had a pleural fluid adenosine deaminase level of ≤100 U/L. When analysis was restricted to 689 patients with pleural fluid adenosine deaminase level of ≤100 U/L and early negative findings for malignancy and non-tuberculous infection in pleural fluid, the positive predictive value was significantly increased and the negative predictive value non-significantly reduced. Using this approach, neither additionally restricting analysis to exudates by Light's criteria nor adding closed pleural biopsy would further enhance predictive values. As such, the diagnostic cut-off value for pleural fluid adenosine deaminase is 26.5 U/L, with a sensitivity of 87.3%, specificity of 93.2%, positive predictive value of 79.2%, negative predictive value of 96.1%, and accuracy of 91.9%. Sex, age, and co-morbidity did not significantly affect prediction of tuberculous pleural effusion using the cut-off value. We have established a diagnostic cut-off level for pleural fluid adenosine deaminase in the diagnosis of tuberculous pleural effusion by restricting analysis to a level of ≤100 U/L, and considering early pleural fluid findings for malignancy and non-tuberculous infection, but not Light's criteria.

Sudden arrhythmia death syndrome (SADS) accounts for about 30% of causes of sudden cardiac death (SCD) in young people. In Hong Kong, there are scarce data on SADS and a lack of experience in molecular autopsy. We aimed to investigate the value of molecular autopsy techniques for detecting SADS in an East Asian population. This was a two-part study. First, we conducted a retrospective 5-year review of autopsies performed in public mortuaries on young SCD victims. Second, we conducted a prospective 2-year study combining conventional autopsy investigations, molecular autopsy, and cardiac evaluation of the first-degree relatives of SCD victims. A panel of 35 genes implicated in SADS was analysed by next-generation sequencing. There were 289 SCD victims included in the 5-year review. Coronary artery disease was the major cause of death (35%); 40% were structural heart diseases and 25% were unexplained. These unexplained cases could include SADS-related conditions. In the 2-year prospective study, 21 SCD victims were examined: 10% had arrhythmogenic right ventricular cardiomyopathy, 5% had hypertrophic cardiomyopathy, and 85% had negative autopsy. Genetic analysis showed 29% with positive heterozygous genetic variants; six variants were novel. One third of victims had history of syncope, and 14% had family history of SCD. More than half of the 11 first-degree relatives who underwent genetic testing carried related genetic variants, and 10% had SADS-related clinical features. This pilot feasibility study shows the value of incorporating cardiac evaluation of surviving relatives and next-generation sequencing molecular autopsy into conventional forensic investigations in diagnosing young SCD victims in East Asian populations. The interpretation of genetic variants in the context of SCD is complicated and we recommend its analysis and reporting by qualified pathologists.

Reference intervals (RIs) are essential tool for proper interpretation of results. There is a global trend towards implementing common RIs to avoid confusion and enhance patient management across different laboratories. However, local practices with respect to RIs lack harmonisation. We have conducted the first local survey regarding RIs for 14 general chemistry analytes in 10 chemical pathology laboratories that employ four different analytical platforms (Abbott Architect, Beckman Coulter AU, Roche Cobas, and Siemens Dimension EXL). Analytical bias was assessed by an inter-laboratory results comparison of external quality assurance programmes. Sufficient inter-laboratory and inter-platform agreement regarding the 10 analytes (albumin, alanine aminotransferase, aspartate aminotransferase, chloride, gamma-glutamyl transferase, phosphate, potassium, sodium, total protein, and urea) were demonstrated. However, the RIs were heterogeneous across all laboratories, with percentage differences of the upper RI value of up to 47% for aspartate aminotransferase (absolute difference of 16 U/L), 29% for urea (1.8 mmol/L), and 18% for potassium (0.8 mmol/L). The percentage difference between lower RI values was up to 24% for urea (0.6 mmol/L), 22% for phosphate (0.16 mmol/L), and 8% for total protein (5 g/L). The coefficients of variation of the upper RI values of potassium and sodium were 1.2 times and 1.0 times of their corresponding between-subject biological variation, respectively, representing unnecessary variations that are overlooked and unchecked in current practice. We recommend the use of common RIs for general chemistry analytes in Hong Kong to prevent interpreter confusion, improve electronic data transfer, and unite laboratory practice. This is the first local study on this topic, and our data can lay the groundwork for increasing harmonisation of RIs across more laboratory tests.

Newborn screening is important for early diagnosis and effective treatment of inborn errors of metabolism (IEM). In response to a 2008 coroners' report of a 14-year-old boy who died of an undiagnosed IEM, the OPathPaed service model was proposed. In the present study, we investigated the feasibility of the OPathPaed model for delivering expanded newborn screening in Hong Kong. In addition, health care professionals were surveyed on their knowledge and opinions of newborn screening for IEM. The present prospective study involving three regional hospitals was conducted in phases, from 1 October 2012 to 31 August 2014. The 10 steps of the OPathPaed model were evaluated: parental education, consent, sampling, sample dispatch, dried blood spot preparation and testing, reporting, recall and counselling, confirmation test, treatment and monitoring, and cost-benefit analysis. A fully automated online extraction system for dried blood spot analysis was also evaluated. A questionnaire was distributed to 430 health care professionals by convenience sampling. In total, 2440 neonates were recruited for newborn screening; no true-positive cases were found. Completed questionnaires were received from 210 respondents. Health care professionals supported implementation of an expanded newborn screening for IEM. In addition, there is a substantial need of more education for health care professionals. The majority of respondents supported implementing the expanded newborn screening for IEM immediately or within 3 years. The feasibility of OPathPaed model has been confirmed. It is significant and timely that when this pilot study was completed, a government-led initiative to study the feasibility of newborn screening for IEM in the public health care system on a larger scale was announced in the Hong Kong Special Administrative Region Chief Executive Policy Address of 2015.

Hereditary channelopathies and cardiomyopathies are potentially lethal and are clinically and genetically heterogeneous, involving at least 90 genes. Genetic testing can provide an accurate diagnosis, guide treatment, and enable cascade screening. The genetic basis among the Hong Kong Chinese population is largely unknown. We aimed to report on 28 unrelated patients with positive genetic findings detected from January 2006 to December 2015. Sanger sequencing was performed for 28 unrelated patients with a clinical diagnosis of channelopathies or cardiomyopathies, testing for the following genes: and for long QT syndrome; for Brugada syndrome; for catecholaminergic polymorphic ventricular tachycardia; and for hypertrophic cardiomyopathy; for dilated cardiomyopathy; and and for arrhythmogenic right ventricular dysplasia/cardiomyopathy. There were 17 males and 11 females; their mean age at diagnosis was 39 years (range, 1-80 years). The major clinical presentations included syncope, palpitations, and abnormal electrocardiography findings. A family history was present in 13 (46%) patients. There were 26 different heterozygous mutations detected, of which six were novel-two in (NM_198056.2:c.429del and c.2024-11T>A), two in (NM_000256.3:c.906-22G>A and c.2105_2106del), and two in (NM_170707.3:c.73C>A and c.1209_1213dup). We have characterised the genetic heterogeneity in channelopathies and cardiomyopathies among Hong Kong Chinese patients in a 10-year case series. Correct interpretation of genetic findings is difficult and requires expertise and experience. Caution regarding issues of non-penetrance, variable expressivity, phenotype-genotype correlation, susceptibility risk, and digenic inheritance is necessary for genetic counselling and cascade screening.

The recent declaration of Ebola virus disease as epidemic by the World Health Organization indicates urgency for affected countries and their laboratories to evaluate and provide treatment to patients potentially infected by the Ebola virus. A heat inactivation procedure involving treating specimens at 60°C for 60 minutes has been suggested for inactivation of the Ebola virus. This study aimed at evaluating the effect of plasma heating on common biochemical tests. Comparative experimental study. A regional chemical pathology laboratory in Hong Kong. Forty consecutive plasma specimens for general chemistry analytes on Beckman Coulter AU5822 and another 40 plasma specimens for troponin I analysis on Access 2 Immunoassay System were obtained, anonymised, and divided into two aliquots. One aliquot was analysed directly and the other was analysed after heating at 60°C for 60 minutes. A total of 20 chemical pathology tests were evaluated. Nine tests (sodium, potassium, chloride, urea, creatinine, total calcium, phosphate, total protein, and glucose) were not significantly affected by the heat inactivation procedure and remained clinically interpretable. Results for magnesium (15% mean increase), albumin (41% mean increase), bilirubin (8% mean decrease), amylase (27% mean decrease), and troponin I (76% mean decrease) were still interpretable using regression estimation with proportional bias. However, all enzymes studied except amylase (alanine transaminase, aspartate transaminase, alkaline phosphatase, gamma-glutamyltransferase, creatine kinase, and lactate dehydrogenase) were inactivated to a significant degree. Their Pearson r or Spearman rho values ranged from no significant correlation (P≥0.05) to 0.767, and most normality was rejected. Heat inactivation results in no significant change in electrolytes, glucose, and renal function tests, but causes a significant bias for many analytes. Recognition of the relationship between pre- and post-heat inactivation specimens allows clinical interpretation of affected values and contributes to patient care. For safety and diagnostic accuracy, we recommend use of a point-of-care device for blood gases, electrolytes, troponin, and liver and renal function tests within a class 2 or above biosafety cabinet with level 3 or above biosafety laboratory practice.

Background: We investigated the mechanisms leading to allele dropout—the nonamplification of 1 of the alleles—in PCR-based diagnosis of Wilson disease (WD). Methods: We extracted genomic DNA from blood samples from 6 WD patients (P1–P6) with allele dropouts detected in a previous study of WD in a Hong Kong Chinese population. We amplified the ATP7B gene by PCR and performed direct DNA sequencing of all exons of the ATP7B gene. To support the proposed mechanism of allele dropout, we used proofreading DNA polymerase, primer design avoiding single-nucleotide polymorphism sites, and duplex PCR. Results: Patients P1–P4 were all apparently homozygous for a known disease-causing mutation, c.2975C>T (p.P992L) in exon 13. Patient P5 was apparently homozygous for a novel mutation, c.2524G>A, and patient P6 was apparently homozygous for another known mutation, c.522_523insA (p.K175K-fs). In all cases, we determined that the patients were actually heterozygous for these mutations. Conclusion: Our results confirm that allele dropout is the mechanism causing apparent homozygosity of heterozygous mutations in these WD patients.