SARS-CoV-2 seropositivity amongst healthcare workers in South Africa during the Omicron wave: natural infection versus vaccination.

Aims: Concerns over population-level immunity have been heightened with each successive wave of COVID-19, prompting questions about whether it is primarily derived from vaccination efforts or from previous natural infections with the virus. We wished to determine the seroprevalence of SARS-CoV-2 antibodies among healthcare workers (HCWs) in Pretoria (Tshwane), South Africa, and to establish whether they were derived from vaccination or natural infection.

Methods: Serum samples were collected from HCWs during the fourth wave of COVID-19 between 1 December 2021 and 13 March 2022.

Real world feasibility of patient-based real time quality control (PBRTQC) using five analytes in a South African laboratory.

Background: Patient-based real-time quality control (PBRTQC) identifies possible bias in methods by utilising shifts in trend of statistical measures in laboratory results. In this study we aimed to compare and optimize various PBRTQC procedures for serum alanine aminotransferase, albumin, calcium, ferritin and sodium.

Methods: In a bias simulation study, we added artificial bias to intervals of patient data and then evaluated the efficiency with which various PBRTQC procedures were able to detect this bias.

A framework for implementing best laboratory practices for non-integrated point of care tests in low resource settings.

The method we respond to pandemics is still inadequate for dealing with the point of care testing (POCT) requirements of the next large epidemic. The proposed framework highlights the importance of having defined policies and procedures in place for non-integrated POCT to protect patient safety. In the absence of a pathology laboratory, this paradigm may help in the supply of diagnostic services to low-resource centers.

Calculated LDL-cholesterol: comparability of the extended Martin/Hopkins, Sampson/NIH, Friedewald and four other equations in South African patients.

Aims: The reference method for low-density lipoprotein-cholesterol (LDL-C) is ultracentrifugation. However, this is unsuitable for routine use and therefore direct LDL-C assays and predictive equations are used. In this study, we compared the Friedewald, extended Martin/Hopkins, Sampson/NIH and four other equations to a direct assay.

Neonatal presentation of a patient with Liddle syndrome, South Africa.

Introduction: Liddle syndrome is an autosomal dominantly inherited disorder usually arising from single mutations of the genes that encode for the alpha, beta and gamma epithelial sodium channel (ENaC) subunits. This leads to refractory hypertension, hypokalaemia, metabolic alkalosis, hyporeninaemia and hypoaldosteronism, through over-activation of the ENaC.

Case Presentation: We describe a 5-day old neonate who presented with severe hypernatraemic dehydration requiring admission to Steve Biko Academic Hospital in South Africa in 2012.

Performance of equations for calculated LDL-C in hypertriglyceridaemia: Which one correlates best with directly measured LDL-C?

Background: The gold standard for measuring LDL-C is impractical and direct measurements have numerous shortcomings. Older predictive equations are used only with triglycerides (TG's) below 4.52 mmol/L.

25-Hydroxycholecalciferol Inhibits Cell Growth and Induces Apoptosis in SiHa Cervical Cells via Autocrine Vitamin D Metabolism.

Preclinical studies show that the anticancer actions of vitamin D metabolites are mediated by apoptosis, inhibition of cell proliferation and induction of cell cycle arrest. Cervical cancer cells express an autocrine vitamin D metabolising system (VDMS) comprised of a vitamin D receptor, vitamin D catabolic enzyme (CYP24A1), and the activating enzyme of 25-hydroxycholecalciferol (25(OH)D3), CYP27B1. We assessed the anticancer effects of 25(OH)D3 at clinically relevant concentrations on a cervical squamous cell cancer cell line, SiHa.

Best practice for LDL-cholesterol: when and how to calculate.

The lipid profile is important in the risk assessment for cardiovascular disease. The lipid profile includes total cholesterol, high-density lipoprotein (HDL)-cholesterol, triglycerides (TGs) and low-density lipoprotein (LDL)-cholesterol (LDL-C). LDL-C has traditionally been calculated using the Friedewald equation (invalid with TGs greater than 4.

Comparability of calculated LDL-C with directly measured LDL-C in selected paediatric and adult cohorts.

Background And Aims: The gold standard for measuring LDL-C is impractical for routine use while direct measurements have numerous shortcomings. This study investigated the correlation of predictive equations with currently used enzymatic assays in populations where these have historically proven unreliable to determine whether equations may be used interchangeably. No reference measure was available for comparison in this study.

How should low-density lipoprotein cholesterol be calculated in 2022?

Purpose Of Review: The reference method for low-density lipoprotein-cholesterol (LDL-C) quantitation is β-quantification, a technically demanding method that is not convenient for routine use. Indirect calculation methods to estimate LDL-C, including the Friedewald equation, have been used since 1972. This calculation has several recognized limitations, especially inaccurate results for triglycerides (TG) >4.

Comparability of 11 different equations for estimating LDL cholesterol on different analysers.

Objectives: Low-density lipoprotein cholesterol (LDL-C) estimation is critical for risk classification, prevention and treatment of atherosclerotic cardiovascular disease (ASCVD). Predictive equations and direct LDL-C are used. We investigated the comparability between the Martin/Hopkins, Sampson, Friedewald and eight other predictive equations on two analysers, to determine whether the equation or analyser influences predicted LDL-C result.

Application of Single-Domain Antibodies ("Nanobodies") to Laboratory Diagnosis.

Antibodies have proven to be central in the development of diagnostic methods over decades, moving from polyclonal antibodies to the milestone development of monoclonal antibodies. Although monoclonal antibodies play a valuable role in diagnosis, their production is technically demanding and can be expensive. The large size of monoclonal antibodies (150 kDa) makes their re-engineering using recombinant methods a challenge.

Hyperthyroidism in molar pregnancy: β-HCG levels do not always reflect severity.

Background: Molar pregnancy is a complication characterised by abnormal benign or malignant proliferation of trophoblastic cells resulting in markedly elevated β-hCG (human chorionic gonadotrophin) levels, an established marker for the presence of the disease. Owing to the structural homology between β-hCG and TSH, the raised β-hCG can result in secondary hyperthyroidism.

Methods: Two patients aged 20 (Case 1) and 31 years (Case 2) presented to the emergency department within a few days of each other complaining of vaginal bleeding associated with abdominal pain.

Molecules in pathogenesis: angiotensin converting enzyme 2 (ACE2).

The renin-angiotensin system is mainly associated with the regulation of blood pressure, but recently many other functions of this system have been described. ACE2, an 805-amino acid monocarboxypeptidase type I transmembrane glycoprotein, was discovered in 2000 and has sequence similarity to two other proteins, namely ACE and collectrin. The ACE2 gene is located on Xp22 and is highly polymorphic.

Critical evaluation of equations for serum osmolality: Proposals for effective clinical utility.

Background: Many studies have assessed the predictive accuracy of serum osmolality equations. Different approaches for selecting a usable equation were compared using thirty published equations and patient data from a regional hospital laboratory.

Methods: Laboratory records were extracted with same-sample results for measured serum osmolality, sodium, potassium, urea and glucose analysed in a regional hospital laboratory between 1/1/2017-31/12/2018.

Historical perspectives in clinical pathology: Bence Jones protein-early urine chemistry and the impact on modern day diagnostics.

This is the third in the series of historical articles dealing with developments in clinical pathology. Bence Jones proteins are immunoglobulin light chains found in excessive quantities in urine in multiple myeloma and are believed to be one of the first tumour markers ever discovered . Dr Henry Bence Jones is credited with the discovery of this protein in 1847 that bears his name and he can also be regarded as the first chemical pathologist/clinical chemist.

Gene of the month: .

Apolipoprotein L1 (APOL1) is a protein encoded by the gene, found only in humans and several primates. Two variants encoding two different isoforms exist for , namely G1 and G2. These variants confer increased protection against trypanosome infection, and subsequent African sleeping sickness, and also increase the likelihood of renal disease in individuals of African ancestry.

Gene of the month: the 2019-nCoV/SARS-CoV-2 novel coronavirus spike protein.

The year 2020 has seen a major and sustained outbreak of a novel betacoronavirus (severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2) infection that causes fever, severe respiratory illness and pneumonia, a disease called COVID-19. At the time of writing, the death toll was greater than 120 000 worldwide with more than 2 million documented infections. The genome of the CoV encodes a number of structural proteins that facilitate cellular entry and assembly of virions, of which the spike protein S appears to be critical for cellular entry.

Five years of screening for galactosaemia in South Africa: Pitfalls of using Benedict's test and thin layer chromatography to screen for galactosaemia in a developing country.

Background: The objective of the study was to investigate the effectiveness of screening for hereditary galactosaemia with Benedict's test and thin layer chromatography (TLC) in a tertiary laboratory from a developing country.

Methods: We retrospectively analysed the results of tests done in suspected galactosaemia patients including Benedict's test, thin layer chromatography, GALT activity and DNA analysis.

Results: 878 paediatric patients were screened with Benedict's test; the age range was 5 days to 19 years.

Mevalonate kinase deficiency masked by cytomegalovirus infection and obscure liver disease.

Background: Chronic liver disease with conjugated hyperbilirubinaemia and failure to thrive can have multifactorial aetiologies. Investigations can be complex and difficult especially when obscured by a viral infection affecting liver function.

Methods: A 5 month old male infant was referred for investigation of chronic liver disease and a history of jaundice with multiple febrile episodes.