African Journal of Laboratory Medicine最新文献

Background: As a novel and deadly acute respiratory syndrome, which later became known as coronavirus disease 2019 (COVID-19), spread beyond China in late January 2020, there were no laboratories in Africa that could test for the disease. However, in early March, just over a month later, 42 African countries had developed the expertise and resources to perform COVID-19 testing. Our goal was to document this public health success story, learn from it, and use it to inform future public health action.

Intervention: Three groups were primarily responsible for establishing COVID-19 testing capacity in Africa. The first group comprised early test manufacturers who reacted with incredible speed and ingenuity early in the pandemic, such as the German company TIB MolBiol that developed a molecular test for COVID-19 before the SARS-CoV-2 genome sequence was available. The second group included private and public donors such as the Jack Ma Foundation, and the last were the coordinators of the rollout, such as the World Health Organization and the Africa Centres for Disease Control and Prevention (CDC).

Lessons learnt: The first lesson was that speed is critical, especially during a crisis. It was also demonstrated that being a predictable and transparent trusted institution opens doors and improves effectiveness. Africa CDC, which was only three years old, was able to secure significant resources from external partners and rapidly build substantial testing capacity within Africa because it is a trusted institution.

Recommendations: Low- and middle-income countries must build local trusted institutions to better prepare for public health challenges.

Background: Diabetic kidney disease is a major complication resulting from type 1 and type 2 diabetes. Currently, the microalbuminuria test is used to monitor renal function; however, it does not detect albumin until progressive loss of renal function has occurred.

Objective: This study analysed the relationship between changes in amino acid ratios and estimated glomerular filtration rate (eGFR) decline in diabetic and non-diabetic patients.

Methods: Urine samples were collected from participants between February 2019 to April 2019 and analysed from November 2020 to January 2021. Diabetic (glycated haemoglobin > 6.4%) and non-diabetic patients (glycated haemoglobin ≤ 6.4%) from Chris Hani Baragwanath Hospital, South Africa, were further categorised based on the degree of renal function predicted by the eGFRs. Amino acids were quantified using tandem mass spectrometry to determine the concentrations and ratios of tyrosine/phenylalanine, ornithine/arginine, arginine/citrulline and citrulline/ornithine at different stages of the chronic kidney disease.

Results: Among diabetic patients, the tyrosine/phenylalanine ratio showed a statistically significant increase (p = 0.04) as the eGFR declined from stage 1 to stage 4; the ornithine/arginine ratio showed a strong negative correlation with eGFR. The citrulline/ornithine ratio differed between the diabetic and non-diabetic patients in stage 1 of chronic kidney disease.

Conclusion: Amino acid ratios (ornithine/arginine and tyrosine/phenylalanine) are affected by the progression of diabetes and can be correlated to renal function. The citrulline/ornithine ratios differ between the studied groups in stage 1 of the disease and may be utilised to predict the onset of chronic kidney disease.

A retrospective review of liquid mycobacterial cultures was performed at a laboratory in South Africa from 01 January 2018 to 31 December 2018 to assess the increased yield in detecting Mycobacterium tuberculosis complex following sample re-decontamination. Only 9 of 99 (9%) re-decontaminated samples were culture positive for M. tuberculosis complex. Xpert MTB/RIF Ultra, concurrently performed on 7 of the 9 samples, detected M. tuberculosis complex in all but 1 sample. Re-decontamination of non-sterile samples did not increase the M. tuberculosis complex yield enough to offset the financial costs and additional labour in a laboratory that utilises the Xpert MTB/RIF Ultra system as a first-line diagnostic modality.

Background: Globally, tuberculosis remains a major cause of mortality, with an estimated 1.3 million deaths per annum. The Xpert MTB/RIF assay is used as the initial diagnostic test in the tuberculosis diagnostic algorithm. To extend the national tuberculosis testing programme in South Africa, mobile units fitted with the GeneXpert equipment were introduced to high-burden peri-mining communities.

Objective: This study sought to assess the cost of mobile testing compared to traditional laboratory-based testing in a peri-mining community setting.

Methods: Actual cost data for mobile and laboratory-based Xpert MTB/RIF testing from 2018 were analysed using a bottom-up ingredients-based approach to establish the annual equivalent cost and the cost per result. Historical cost data were obtained from supplier quotations and the local enterprise resource planning system. Costs were obtained in rand and reported in United States dollars (USD).

Results: The mobile units performed 4866 tests with an overall cost per result of $49.16. Staffing accounted for 30.7% of this cost, while reagents and laboratory equipment accounted for 20.7% and 20.8%. The cost per result of traditional laboratory-based testing was $15.44 US dollars (USD). The cost for identifying a tuberculosis-positive result using mobile testing was $439.58 USD per case, compared to $164.95 USD with laboratory-based testing.

Conclusion: Mobile testing is substantially more expensive than traditional laboratory services but offers benefits for rapid tuberculosis case detection and same-day antiretroviral therapy initiation. Mobile tuberculosis testing should however be reserved for high-burden communities with limited access to laboratory testing where immediate intervention can benefit patient outcomes.

[This corrects the article DOI: 10.4102/ajlm.v9i1.1114.].

Background: Ebola virus emerged in West Africa in December 2013. The ease of mobility, porous borders, and lack of public health infrastructure led to the largest Ebola virus disease (EVD) outbreak to date.

Intervention: The 2013 EVD outbreak signalled the need for laboratory diagnostic capabilities in areas without strong public health systems. As part of the United States' Department of Defense response, MRIGlobal was contracted to design, fabricate, equip, deploy, and operate two mobile diagnostic laboratories (MDLs). The first laboratory analysed blood samples from patients in an adjacent Ebola Treatment Centre (ETC) and buccal swabs from the deceased in the community in Moyamba, Sierra Leone. The second laboratory was deployed to support an ETC in Conakry, Guinea. The Department of Defense provided real-time quantitative reverse transcription polymerase chain reaction assays that were deployed and validated on-site.

Lessons learnt: Prompt and accurate molecular diagnostics reduced sample turn-around times from over 24 h to under 4 h. Experienced laboratory staff tested up to 110 samples per day and on-site engineering proved necessary for MDL setup and operation. As the Ebola response slowed, the sustainment of the MDLs' operations was prioritised, including staff training and the transition of the MDLs to local governments. Training programmes for local staff were prepared in Sierra Leone and Guinea.

Recommendations: The MRIGlobal MDL team significantly contributed to establishing increased laboratory capacity during the EVD outbreak in West Africa. Using the MDLs for molecular diagnosis is highly recommended until more sustainable solutions can be provided.

Background: Molecular red cell genotyping is devoid of serology limitations such as the scarcity of rare antisera and the possibility of inconclusive results due to biological interferences. Blood incompatibility can result in immune transfusion reactions such as haemolytic transfusion reactions or haemolytic disease of the foetus and newborn.

Objective: The study aimed to use molecular red cell genotyping to identify rare blood group donors among South African blood donors.

Methods: Red cell genotyping data were extracted retrospectively from the BIDS XT genotyping software in the Immunohaematology Reference Laboratory from January 2015 to August 2016. The ID CORE XT genotyping assay was used to identify the single nucleotide polymorphisms of 10 blood groups system alleles in 150 donors. Associations between the resultant genotypes and predicted phenotypes, ABO group, RhD type, race group and gender were studied.

Results: Significant red cell genetic variability was noted among the numerous South African donor genotypes identified in this study. Genotyping further confirmed the presence of at least one of the 16 rare genotypes in 50 donors. Group O Black donors were associated with two rare blood types, while several other rare blood types were found only in White donors, supporting an association between ABO/Rh subtype, race group and rare blood types.

Conclusion: Targeted screening of donors for antigen-negative rare blood units for patients should be done to reduce the risk of haemolytic transfusion reactions and haemolytic disease of the foetus and newborn.