Volume 46, Issue 2

The National Biobank of the National Health Laboratory Service (NHLS) is a national treasure established to serve as support infrastructure for the provision of high quality human biological materials for research purposes and it represents the first of its kind in South Africa. This article aims to demonstrate the alignment of the NHLS Biobank to international best practices and guidelines with reference to the 13 sections of the International Society of Biological and Environmental Repositories (ISBER) Best Practices for Repositories (4th ed.). The NHLS Biobank has implemented procedures and management strategies that are technical best practices covering the lifecycle of biobanking (collection, processing, storage and dissemination of human biological materials) while having respect for ethical and regulatory processes, upholding the interest of the donors. ISBER best practices are invaluable sources of guidance and benchmarking on the guiding principles has enabled the NHLS Biobank to develop into an entity with infrastructure and operational activities that support its short-term and long-term objectives that are set out in the business plan.

Objectives Due to massive screening of the persistent coronavirus SARS-CoV-2, supply difficulties emerged for swabs and extraction reagents leading to test alternative choices. Quality sampling may have an impact on the result and a low RNA detection may be difficult to interpret because it does not necessarily mean that infectious particles are present in biological samples. There is a need to understand whether the Ct value information is relevant and informative. Methods We compared the pre-analytical stability of RNA in saline solution, UTM ® , Amies and Cary-Blair transport media. Expression profile of E , N and RdRp genes was assessed at various concentration levels with the Allplex™ 2019-nCoV Assay. Factors that may influence the determination of Ct were studied with several extraction reagents coupled to the GSD NovaPrime ® SARS-CoV-2 RT-PCR testing kit. Results Seventy two-hour RNA stability has been demonstrated for all the transport media assessed. A matrix effect was shown, leading to a decrease in the detection of E and RdRp genes, so that only N gene was often found for Ct greater than 35.0. A follow-up over more than 67,000 patients suggests that N gene may be a sensitive indicator to detect a new active viral circulation, but establishing a correlation between a positive threshold and a low risk of infection for a given method remains difficult. Conclusions Several transport media and extraction processes are suitable for PCR-based SARS-CoV-2 detection. During periods of active virus circulation, any weakly positive results should be considered.

Objectives An effective vaccine against SARS-CoV-2 is essential to mitigate the COVID-19 pandemic. In these several months, a number of groups have started to report humoral responses and side effects after BNT162b2 vaccinations. Although these reports demonstrate the safety and efficacy, further studies are warranted to verify these findings. Here we examined the levels of SARS-CoV-2 antibodies in Japanese healthy volunteers who underwent BNT162b2 vaccine, to assess the humoral responses and side effects. Methods Forty-one healthy volunteers’ samples were used for the measurement of SARS-CoV-2 antibodies with chemiluminescent assays against the Receptor Binding Domain (RBD) of the virus. We also measured the side effects of the vaccination. Results Although the levels of IgM varied, all participants were seronegative for IgM and IgG before vaccination, and both IgM and IgG were significantly increased after the vaccinations. We further analyzed the humoral responses in relation to age, and found that the IgG levels for 14 days and 35 days, and IgM levels for 14 days after vaccination showed clear declining trends with age. Commonly reported side effects in the participants were sore arm/pain (90.0%) after the first dose, and generalized weakness/fatigue (70.0%), fever (57.5%), and sore arm/pain (90.0%) after the second dose. Conclusions BNT162b2 vaccination generates sufficient production of IgG especially after the second dose, though the response decreases age-dependently. The high frequencies of generalized weakness/fatigue, fever, and sore arm/pain were not negligible, especially after the second dose. This may be associated with the age characteristics of the population.

Objectives To investigate the influence of preservation methods and processes on the plasma interleukin-6 (IL-6) stability. Methods Lithium-heparin plasma was collected from female patients: 32 female patients with invasive breast neoplasms and 20 healthy females. Each sample was divided into three tubes. Samples were stored at different temperatures or at different times. The concentration of IL-6 was detected. Results IL-6 levels in patients were not altered significantly compared to the control group after storage at 4 °C or 25 °C for 12 h. However, IL-6 levels were significantly higher compared to controls (p<0.05) after storage at 25 °C for 48 h. IL-6 levels in patients with breast neoplasms were significantly higher compared to the control group (p<0.05) when stored at 4 °C after 12 h. IL-6 levels in patients with breast neoplasm increased more than 10-folds compared to the control group after only 2 h storage at 25 °C. Conclusions Concentrations of IL-6 in breast neoplasms samples significantly change under different storage conditions. Pretreatment needs to be standardized for blood sample handling procedure. Comparison of different storage conditions of IL-6 levels may not be reliable.

Objectives Serum ferritin (SF) is a biomarker of physiological iron stores. Reference intervals for ferritin about children are the subject of some controversy. Methods SF was assayed on Beckman analyzer. All results were retrieved from the electronic medical record (3,344 samples). Student’s t test and one-way ANOVA test were applied to compare two groups, with respect to continuous and discrete variables. Results The reference range of SF on reference population was 8.40–95.98 µg/L. Among the male, there was no significant difference in the average level between the 0–1 years old group and the 1–3 years old group, but there were significant differences between the other groups and the previous group. In terms of women, there was no significant difference in the average level of ferritin between the 1–3 years old group and 9–17 years old group and the previous group, but there were significant differences in the average levels of ferritin in other groups. Conclusions We established the reference intervals of ferritin of different age groups and gender groups. Our results have practical significance for the formulation of clinical reference range, which would be helpful in interpreting laboratory data and clinical decision-making.

Objectives The aim of this study was to establish reference intervals (RIs) of homocysteine (Hcy) in healthy Chinese Han ethnic adults according to the Clinical and Laboratory Standard Institute (CLSI) CA28-A3. Methods After filtering, serum Hcy values in 20,810 healthy subjects from a middle area of China (Wuhu, Anhui province) were measured. The non-parametrical percentile method was used to establish RIs and the 90% confidence intervals of lower and upper limits were calculated. The relationship between Hcy and age was analyzed by using Spearman’s approach. Besides, the risk of HHcy in males and females was examined by logistic regression analysis. Results The RIs of Hcy were 9.10–20.20 μmol/L for males, 6.10–15.90 μmol/L for females and 8.00–19.80 μmol/L for total subjects from 20 to 90 years old. The serum Hcy level was significantly correlated with age both in males (r=0.2159, p<0.0001) and females (r=0.2955, p<0.0001). In males, the prevalence and the risk of HHcy were higher than females of all ages (p<0.001). Conclusions Through the analysis of a large dataset from healthy population, it showed that the variations in different age- and sex-related RIs of Hcy were significant. It suggested that establishing more specific age- and sex-related RIs for Hcy in China is necessary.

Objectives The application of Sigma metrics can be used for assessing the performance of diagnostic laboratories. Clinical laboratories are confronted with the trouble of having to select the best and suitable quality specifications that are required for quality planning. In this regard, our study aims at evaluating the performance of Sysmex XN-1000 hematology analyzer by using Sigma metrics based on different total allowable error (TEa) source and to determine the effects of these variations in Sigma metric evaluation. Methods Five TEa requirements were selected to calculate Sigma metrics of 11 complete blood count (CBC) parameters. Coefficient of variation (CV) and bias data were supplied from internal quality control (IQC) and External Quality Assessment Scheme (EQAS) respectively. Results According to TEa based on desirable biological variation (BV) database specifications, the highest Sigma value was achieved by white blood cell count for each level, the lowest value was achieved by Red Cell Distribution Width-Standard Deviation parameter. The Sigma calculation based on Spanish TEa showed that seven CBC parameter achieved Sigma value ≥3. Conclusions According to the results of the study, it can be concluded that Sigma scores have a significant fluctuation based on which TEa sources are utilized and the need for Sigma metrics harmonization and standardization is highlighted. Additionally, low Sigma values of most CBC parameters are resulted in the conclusion that the use of performance goals depending on BV data is difficult for common clinical use. Therefore, clear standardized criteria are quite necessary for the selection of TEa goal by laboratories.