1.Evaluation of the dried blood spot (DBS) collection method as a tool for detection of HIV Ag/Ab, HBsAg, anti-HBs and anti-HCV in a Malaysian tertiary referral hospital.
Chee Eng LEE ; Sasheela Sri PONNAMPALAVANAR ; Sharifah Faridah Syed OMAR ; Sanjiv MAHADEVA ; Lai Yee ONG ; Adeeba KAMARULZAMAN
Annals of the Academy of Medicine, Singapore 2011;40(10):448-453
INTRODUCTIONDried blood spot (DBS) collection is an appealing alternative to whole blood or plasma sampling, as it has technical and economic advantages over the latter.
MATERIALS AND METHODSA prospective cross-sectional study was conducted at a Malaysian tertiary referral hospital from November 2009 to March 2010. One hundred and fifty paired specimens of DBS and plasma were analysed by the standard assays for HIV Ag/Ab, HBsAg, anti-HBS and anti-HCV, separately (total 600 paired specimens). DBS sample titres were then compared to the results of plasma testing, which was used as the gold standard.
RESULTSFor the HIV Ag/Ab assay with a cut-off point of 0.35 Relative Light Units (RLUs), the sensitivity and specificity were both 100%. For the HBsAg assay, the sensitivity was 96.5% and the specificity was 97.8%, with a cut-off point of 1.72 RLUs. Sensitivity for the anti-HBs test was 74.2% and the specificity was 86.9%, using a cut-off point of 0.635 RLUs. For the anti-HCV assay, the sensitivity was 97.3% and the specificity was 100%, with a cut-off point of 0.10 RLUs.
CONCLUSIONDBS is an ideal choice to be used as a screening tool for the detection of HIV, Hepatitis B and Hepatitis C virus infections. However, different cut-off values need to be used for the validation of test positivity in DBS samples because the small amount of blood in the DBS specimens leads to lower assay titres.
Cross-Sectional Studies ; Dried Blood Spot Testing ; HIV Antibodies ; blood ; immunology ; HIV Antigens ; blood ; immunology ; HIV Infections ; diagnosis ; Hepacivirus ; isolation & purification ; Hepatitis B ; diagnosis ; Hepatitis B Antibodies ; blood ; immunology ; Hepatitis B Surface Antigens ; blood ; immunology ; Hepatitis C ; diagnosis ; Hepatitis C Antibodies ; blood ; immunology ; Hepatitis C Antigens ; blood ; immunology ; Humans ; Malaysia ; Plasma ; virology ; Prospective Studies ; Referral and Consultation ; Sensitivity and Specificity ; Specimen Handling
2.Reference range for ADAMTS13 antigen, activity and anti-ADAMTS13 antibody in the healthy adult Singapore population.
Allison Ching Yee TSO ; Christina Lai Lin SUM ; Kiat Hoe ONG
Singapore medical journal 2022;63(4):214-218
INTRODUCTION:
ADAMTS13 (a disintegrin-like and metalloproteinase with a thrombospondin Type 1 motif, member 13) plays a fundamental role in the regulation of haemostasis and thrombosis. Its deficiency leads to an accumulation of ultra-large von Willebrand multimers, inducing spontaneous platelet aggregation, thrombosis in the microvasculature, and thrombotic thrombocytopenic purpura (TTP), a condition with 90% mortality when left untreated. Prompt quantification of ADAMTS13 antigen, activity and autoantibody plays a crucial role in the diagnosis and management of TTP and can help differentiate it from other thrombotic microangiopathies (TMAs). Reference ranges for ADAMTS13 are generally derived from Caucasian patients. Given that polymorphism in the ADAMTS13 gene can be associated with variable ADAMTS13 levels, we aimed to establish the first reference range in Singapore and provide a crucial laboratory test for institutions here and elsewhere.
METHODS:
150 healthy voluntary donors (75 men, 75 women) aged 21-60 years, with an ethnic mix mirroring Singapore's population profile, were recruited. ADAMTS13 antigen, activity and autoantibody levels were measured using the fluorescence resonance energy transfer-vWF73 and enzyme-linked immunosorbent assay methodologies.
RESULTS:
Levels (activity 0.65-1.79 IU/mL, antigen 0.36-1.17 IU/mL, autoantibody 1.4-12.5 U/mL) were not statistically different between the genders and various age groups.
CONCLUSION
TTP and TMAs are encountered in a wide range of specialties. The availability of new assays in Singapore will aid clinicians in the timely management of these conditions. Standardising reference ranges established for Singapore against World Health Organization standards allows harmonisation of measurements between laboratories and for future research collaborations.
ADAMTS13 Protein/analysis*
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Adult
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Enzyme-Linked Immunosorbent Assay
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Female
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Humans
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Male
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Purpura, Thrombotic Thrombocytopenic/diagnosis*
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Reference Values
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Singapore
3.Early Dengue infection and outcome study (EDEN) - study design and preliminary findings.
Jenny G H LOW ; Eng-Eong OOI ; Thomas TOLFVENSTAM ; Yee-Sin LEO ; Martin L HIBBERD ; Lee-Ching NG ; Yee-Ling LAI ; Grace S L YAP ; Chenny S C LI ; Subhash G VASUDEVAN ; Adrian ONG
Annals of the Academy of Medicine, Singapore 2006;35(11):783-789
INTRODUCTIONDengue is a major public health problem in Singapore. Age-specific dengue morbidity rates are highest in the young adult population, unlike in many other Southeast Asian countries where dengue is mainly a paediatric disease. Hence, the World Health Organization (WHO) guidelines on dengue diagnosis and management which were developed using the paediatric experiences, may not be suitable for the management of adult dengue infections.
MATERIALS AND METHODSThe Early DENgue (EDEN) infection and outcome study is a collaborative longitudinal study to investigate epidemiological, clinical, viral and host-specific features of early dengue-infected adults, in an effort to identify new early markers for prognostication. Patients presenting with early undifferentiated fever were included in the study. We carried out an interim analysis to look for early indicators of severe disease.
RESULTSDuring the period of this interim study analysis, 455 febrile patients were recruited. Of these, 133 were confirmed as acute dengue cases based on dengue-specific polymerase chain reaction (PCR) results. There were significant clinical and epidemiological differences between dengue and febrile non-dengue cases. Nine per cent of the dengue cases experienced persistent tiredness, drowsiness and loss of appetite beyond 3 weeks of illness. Quantitation of viral loads using the crossover (Ct) value of real-time RT-PCR correlated with the duration of symptoms. More than half of both primary and secondary dengue cases were hospitalised. There was no dengue-related mortality in this study.
CONCLUSIONThe duration of illness and prolonged symptom duration in 9% of the subjects indicate that the burden of dengue illness is substantially different from other non-dengue febrile illness in our study cohort. Our study also highlights the paucity of early prognostic markers for dengue fever in adults.
Adult ; Antibodies, Viral ; analysis ; Dengue ; diagnosis ; epidemiology ; virology ; Dengue Virus ; genetics ; immunology ; isolation & purification ; Enzyme-Linked Immunosorbent Assay ; Female ; Follow-Up Studies ; Humans ; Male ; Morbidity ; trends ; Prognosis ; RNA, Viral ; analysis ; Retrospective Studies ; Reverse Transcriptase Polymerase Chain Reaction ; Singapore ; epidemiology
4.Singapore Paediatric Resuscitation Guidelines 2016.
Gene Yong Kwang ONG ; Irene Lai Yeen CHAN ; Agnes Suah Bwee NG ; Su Yah CHEW ; Yee Hui MOK ; Yoke Hwee CHAN ; Jacqueline Soo May ONG ; Sashikumar GANAPATHY ; Kee Chong NG ; null ; null
Singapore medical journal 2017;58(7):373-390
We present the revised 2016 Singapore paediatric resuscitation guidelines. The International Liaison Committee on Resuscitation's Pediatric Taskforce Consensus Statements on Science and Treatment Recommendations, as well as the updated resuscitation guidelines from the American Heart Association and European Resuscitation Council released in October 2015, were debated and discussed by the workgroup. The final recommendations for the Singapore Paediatric Resuscitation Guidelines 2016 were derived after carefully reviewing the current available evidence in the literature and balancing it with local clinical practice.
5.Radiographic features of COVID-19 based on an initial cohort of 96 patients in Singapore.
Hau Wei Wei KHOO ; Terrence Chi Hong HUI ; Salahudeen Mohamed Haja MOHIDEEN ; Yeong Shyan LEE ; Charlene Jin Yee LIEW ; Shawn Shi Xian KOK ; Barnaby Edward YOUNG ; Sean Wei Xiang ONG ; Shirin KALIMUDDIN ; Seow Yen TAN ; Jiashen LOH ; Lai Peng CHAN ; Angeline Choo Choo POH ; Steven Bak Siew WONG ; Yee-Sin LEO ; David Chien LYE ; Gregory Jon Leng KAW ; Cher Heng TAN
Singapore medical journal 2021;62(9):458-465
INTRODUCTION:
Chest radiographs (CXRs) are widely used for the screening and management of COVID-19. This article describes the radiographic features of COVID-19 based on an initial national cohort of patients.
METHODS:
This is a retrospective review of swab-positive patients with COVID-19 who were admitted to four different hospitals in Singapore between 22 January and 9 March 2020. Initial and follow-up CXRs were reviewed by three experienced radiologists to identify the predominant pattern and distribution of lung parenchymal abnormalities.
RESULTS:
In total, 347 CXRs of 96 patients were reviewed. Initial CXRs were abnormal in 41 (42.7%) out of 96 patients. The mean time from onset of symptoms to CXR abnormality was 5.3 ± 4.7 days. The predominant pattern of lung abnormality was ground-glass opacity on initial CXRs (51.2%) and consolidation on follow-up CXRs (51.0%). Multifocal bilateral abnormalities in mixed central and peripheral distribution were observed in 63.4% and 59.2% of abnormal initial and follow-up CXRs, respectively. The lower zones were involved in 90.2% of initial CXRs and 93.9% of follow-up CXRs.
CONCLUSION
In a cohort of swab-positive patients, including those identified from contact tracing, we found a lower incidence of CXR abnormalities than was previously reported. The most common pattern was ground-glass opacity or consolidation, but mixed central and peripheral involvement was more common than peripheral involvement alone.
COVID-19
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Humans
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Lung/diagnostic imaging*
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Radiography, Thoracic
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Retrospective Studies
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SARS-CoV-2
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Singapore