African Journal of Laboratory Medicine最新文献

Background: The clinical significance of adenoma is as a result of being a precancerous lesion with long latency, harbouring of invasive carcinoma, bearing similar clinical features with colorectal cancer, and as part of hereditary colorectal cancer syndromes. Over-expression of the cyclooxygenase-2 (COX-2) enzyme has been noticed in adenomas with unfavourable features. However, this information is limited in Africa.

Objective: This study aimed to assess the proportion of adenomas in northern Nigeria that over-express COX-2.

Methods: This 5-year retrospective, descriptive, hospital-based study examined the COX-2 immunohistochemistry of all histologically diagnosed colorectal adenomas in Aminu Kano Teaching Hospital, Kano, Nigeria, between 01 January 2015 and 31 December 2019. Age, sex, site, diagnosis, and grade were obtained from the Kano cancer registry and slide reviews of cases.

Results: There were cases of 29 adenoma (male, n = 20; female, n = 9). Adenoma occurred more commonly among male patients (M:F, 2.2:1), in the age group 40-79 years, and included tubular adenomas (62.1%), tubulovillous adenomas (27.6%), and villous adenomas (10.3%). Over-expression of COX-2 was observed in 3.4%. There was no association between COX-2 expression and age, sex, site, histological subtype, or grade.

Conclusion: Over-expressed COX-2 was observed in only 3.4% of adenomas, which may indicate its early involvement in the spectrum of adenoma-carcinoma sequence.

What this study adds: It provides key information about COX-2 expression in adenoma in an African population, which may serve as a rationale for other studies regarding COX-2 targets for chemoprevention and therapy in adenoma and colorectal cancer.

Background: The burden of sickle cell disease in Western Kenya is substantial; however, there is limited research on the effectiveness of rapid diagnostic tests for the condition.

Objective: This study evaluated the feasibility of using the SICKLECHECK™ rapid test kit for detecting sickle cell disease at Bungoma County Referral Hospital, Kenya.

Methods: A cross-sectional study was carried out between October 2023 and February 2024 and included both healthy children and children with a known haemoglobin phenotype. The SICKLECHECK™ rapid screening test was compared to Bio-Rad^™ high-performance liquid chromatography, which served as the reference standard. Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy were calculated using MedCalc^™ statistical software.

Results: The study involved 194 children (98 girls and 96 boys), aged between 10 weeks and 15 years, with haemoglobin profiles sickle cell negative (n = 78), sickle cell trait (n = 21), and sickle cell disease (n = 95). The SICKLECHECK™ test demonstrated sensitivity, specificity, negative predictive value, and accuracy exceeding 97%, with a positive predictive value of 94.18% for haemoglobin A. It also effectively distinguished between normal (sensitivity 97.44%, specificity 99.14%), carrier (sensitivity 90.48%, specificity 98.27%), and disease (sensitivity 98.95%, specificity 98.99%) phenotypes.

Conclusion: Based on the findings in this study, SICKLECHECK^™ could be a reliable point-of-care diagnostic tool for sickle cell disease. The encouragement of healthcare facilities, especially in resource-limited settings, to adopt the SICKLECHECK^™ rapid test for routine screening and diagnosis of sickle cell disease is recommended.

What this study adds: This study highlights the diagnostic reliability of the SICKLECHECK^™ rapid test in accurately identifying and differentiating sickle cell disease, trait, and normal haemoglobin phenotypes, reinforcing its potential role in strengthening early diagnosis efforts in clinical settings.

Background: Triazole resistance in Aspergillus spp. has therapeutic implications for managing chronic pulmonary aspergillosis (CPA) worldwide. However, antifungal susceptibility testing (AFST) is not routinely performed in Nigeria, a country with a high CPA burden.

Objective: This study aimed to confirm the identity of Aspergillus spp. isolated from patients with CPA using molecular methods, determine their antifungal susceptibility profile, and ascertain phylogenetic relatedness.

Methods: This study examined 47 Aspergillus isolates from sputum samples obtained in a prospective longitudinal study of CPA prevalence among 141 consenting symptomatic tuberculosis patients in Lagos, Nigeria, between June 2021 and May 2022. The preliminary phenotypically identified Aspergillus spp. were further identified by amplifying the calmodulin gene and performing AFST against seven antifungal agents using the Clinical Laboratory Standard Institute (CLSI) micro-dilution method, as well as determining their phylogenetic relatedness.

Results: The 51 patients who met the diagnostic criteria for CPA included 30 (59.0%) male and 21 (41.0%) female patients (age range: 17-68 years). Thirty-six (71.0%) had positive Aspergillus cultures. An isolate, initially identified phenotypically as A. fumigatus, was reidentified as A. pseudonomiae. Phylogenetic analysis on A. fumigatus and A. flavus isolates suggested the absence of clonal transmission. All isolates were susceptible to the tested antifungals.

Conclusion: Clinical Aspergillus isolates from azole-naïve patients with CPA did not demonstrate triazole resistance. Nonetheless, AFST is required for patients on long-term azole therapy and systematic surveillance of clinical and environmental isolates is recommended to detect the emergence of azole-resistant phenotypes.

What this study adds: This study underscores the importance of routine surveillance for antifungal resistance to detect the occurrence of resistance strains early in clinical settings, as this has therapeutic implications for patients harbouring resistant phenotypes.

Background: Chronic kidney disease is a global health crisis, and delays in laboratory testing worsen outcomes. Point-of-care testing (POCT) has shown utility in various settings, but its performance at high creatinine levels seen in advanced chronic kidney disease is variable.

Objective: We evaluated the analytical and clinical performance of the Nova Stat Profile Prime Plus (SPP+) point-of-care analyser among patients on maintenance haemodialysis.

Methods: A prospective study was conducted at Chris Hani Baragwanath Hospital, Johannesburg, South Africa. In phase one (01 June 2023 - 31 July 2023), precision, linearity, and accuracy of SPP+ were assessed using remnant patient samples. Blood gases, electrolytes, and metabolic parameters were compared with the GEM Premier 5000, while urea and creatinine were compared with the Roche cobas c702. In phase two (01 November 2023 - 31 December 2023), SPP+ was clinically validated among adults undergoing haemodialysis. Whole blood was collected pre- and post-dialysis to assess dialysis adequacy and the creatinine index.

Results: In phase one, SPP+ showed acceptable precision (coefficients of variation 0% - 2.7%), linearity, and correlation (r > 0.90). Creatinine showed proportional bias (4.56% [0.33 - 8.80]) at higher concentrations. Among 51 haemodialysis patients (22 women, 29 men; aged 32-51 years), SPP+ showed 88.6% agreement for single pool Kt/V and urea reduction ratio. However, creatinine index agreement was low (34.3%, Cohen's kappa = 0.24, p < 0.0001).

Conclusion: Nova SPP+ was comparable to central laboratory analysis, though caution is needed at high creatinine levels, where central laboratory analysis remains the preferred choice.

What this study adds: This study provides the first South African data on POCT in haemodialysis. The analyser has demonstrated potential for monitoring, but performance concerns remain at high creatinine levels. The findings offer practical guidance for integrating POCT into advanced chronic kidney disease care in a resource-limited setting.

Background: Healthcare students could harbour multidrug-resistant (MDR) and methicillin-resistant Staphylococcus aureus (MRSA). There is a need to understand the extent and factors associated with nasal carriage of these strains.

Objective: This study determined the frequency and risk of nasal S. aureus, and multiple antimicrobial resistance indices among students at Ahmadu Bello University, Zaria, Nigeria.

Methods: This comparative cross-sectional study collected nasal samples from 02 January 2024 to 31 July 2024 from healthcare students at Ahmadu Bello University, Nigeria, which were processed for S. aureus identification. Antimicrobial resistance phenotype was determined by the disk diffusion method. Structured questionnaires were used to collect participants' sociodemographic and risk factor data.

Results: A total of 251 students participated, including 126 (50.2%) men and 125 (49.8%) women (aged 17-44 years). The nasal carriage of S. aureus was 31.5% (79/251) and MRSA was 23.5% (59/251). Clinical-phase students had a higher frequency of nasal MRSA (25%) than preclinical-phase students (22.1%). Staphylococcus aureus resistance against non-beta-lactams was highest for tetracycline (49.4%) and ciprofloxacin (29.1%), with 39.2% (31/79) showing MDR. Medical and pharmacy students had statistically significant higher nasal carriage of MDR-S. aureus (p < 0.05). Students residing in households of 5-8 individuals had the highest nasal MDR-S. aureus carriage (p = 0.0044). Staphylococcus aureus isolates with multiple antimicrobial resistance indices of 0.2 (29.1%) and 0.3 (24%) were the most predominant.

Conclusion: High levels of nasal MRSA and MDR-S. aureus were obtained from this study. The predominance of strains with high antimicrobial resistance indicates sources with high antibiotic use.

What this study adds: To our knowledge, this is the first epidemiological study on the multiple antimicrobial resistance indices of nasal S. aureus in healthcare students in Africa. Moreover, this is the first report to categorises subgroup variation of nasal MDR-S. aureus carriage by the six major groups of healthcare students.

Background: Coronavirus disease 2019 (COVID-19) increases the risk of venous thromboembolism, requiring monitoring of low molecular weight heparin (LMWH) via a time-consuming, costly and often unavailable test - anti-factor Xa (anti-Xa). An affordable, rapid point-of-care alternative, the thromboelastogram, is available, but performance comparisons to anti-Xa are lacking.

Objective: This study evaluated the relationship between anti-Xa and thromboelastogram in patients with COVID-19 receiving LMWH.

Methods: This was a retrospective study of patients with COVID-19 receiving LMWH at Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa, between November 2020 and January 2021. Blood samples tested with thromboelastogram and anti-Xa were drawn at three timepoints (one prior to and two after administration of LMWH). Thromboelastogram parameters comprised reaction time (R-time; onset of testing to the start of clot formation), kinetics time (K-time; start of clot formation until the clot reached 20 mm), and thromboelastogram coagulation index (overall coagulation status of whole blood).

Results: Forty-two patients with COVID-19 (15 male and 27 female) met the study criteria. There was a statistically significant, low to moderate correlation (Spearman's correlation coefficient [r _s 0.43, p = 0.014]) between anti-Xa and thromboelastogram coagulation index. A statistically significant moderate correlation (r _s 0.52, p = 0.002) between anti-Xa and R-time, and a statistically significant low correlation (r _s 0.35, p = 0.049) between anti-Xa and K-time, were found. All correlations were 48 h post admission.

Conclusion: Thromboelastogram coagulation index, R-times and K-times had a statistically significant association with anti-Xa levels in patients with COVID-19. Further research is required regarding their clinical utility.

What this study adds: Thromboelastograms may represent a more cost-effective and accessible option to the conventional anti-Xa test in patients receiving LMWH. However, future research with larger sample sizes, varying disease profiles, and severity of illness is required.

Background: Leukoreduction is a post-processing technique that reduces residual leukocytes in cellular blood components. Previous studies have evaluated these parameters mainly among older generation leuko-filters.

Objective: This study evaluated the immediate effects of pre-storage leukoreduction on red cell indices and the performance efficacy of two newer generation leuko-filters.

Methods: This retrospective analysis collected quality control data before and after leukoreduction for erythrocyte concentrates (ECs) from laboratory registers from the Blood Transfusion Laboratory at the Advanced Centre for Treatment, Research and Education in Cancer in Mumbai, India, for the period January 2015 to December 2019. Data related to red cell indices and performance characteristics for Fresenius and Macopharma filters were included.

Results: A total of 500 records was included in the study. All EC units demonstrated a 99.99% leukocyte log reduction, with both filters showing equal efficacy. Post-leukoreduction haemoglobin concentrations were lower than the pre-leukoreduction for all units (p < 0.001). Of those prepared from 350 mL units, 11.6% (28/240) had haemoglobin levels under 40 g/bag as compared to 1.1% (3/260) among those prepared from 450 mL units. All indices exhibited statistically significant changes after leukoreduction (p < 0.001) except for mean corpuscular haemoglobin (p = 0.215). The Fresenius filter required less time for leukoreduction compared to the Macopharma filter (p < 0.001).

Conclusion: Red cell indices show several changes following leukoreduction. Further studies are needed to assess the microscopic and functional impact of leukoreduction. Leuko-filters vary in their performance characteristics, which may influence vendor selection.

What this study adds: This study found changes among several red cell indices after leukoreduction of ECs, which have not been extensively studied in previous literature. Further, we found that the newer generation leuko-filters differ in specific performance characteristics, which may influence vendor selection.

The World Health Organization identified mpox (formerly known as monkeypox), as a resurgent zoonotic epidemic caused by the mpox virus. It is an emerging and re-emerging pathogen with a range of hosts and geographical distribution worldwide. Peer-reviewed scientific articles from 1958 to 29 August 2024 related to global mpox research were extracted from Web of Science^TM Core Collection and Google Scholar Databases to gauge the extent of the infection. Mpox is marked by a recent resurgence of infections across continents, with Africa being the hardest-hit region. The mpox re-emergence has shown a new mechanism of transmission, with several causes such as a rise in the number of unvaccinated individuals, behaviour risk factors, waning immunity, genetic evolution, and environmental circumstances. Preventive and control measures of mpox include vaccination and patient isolation, while treatment involves antivirals and antibiotics for secondary bacterial infections. Laboratory diagnosis entailing polymerase chain reaction can be effective for routine purposes, but results of serological tests must be interpreted with caution, because of cross-reacting determinants among orthopoxviruses. The structure and classification of the mpox virus, clinical manifestations, pathophysiology, epidemiology, historical antecedent, therapeutics, vaccines, and laboratory diagnosis of the disease are explicated, showcasing mpox as an emerging or re-emerging infection with a potential colossal burden on healthcare, and its classification as an international public health emergency by the World Health Organization.

What this study adds: This review provides the global situation of mpox as an emerging or re-emerging infection, warranting its designation as an international public health emergency.

Background: Chronic lymphocytic leukaemia (CLL) is a haematological neoplasm with characteristic flow cytometric immunophenotyping. Pre-analytical variables impact the quality and reproducibility of flow cytometric data, which could alter the diagnosis from CLL to atypical CLL (aCLL).

Objective: This study investigated the effects of pre-analytical variables, specifically sample age and storage temperature, on the stability of key antigens used in the diagnosis of CLL.

Methods: Serial flow cytometric analyses were performed from January 2022 to March 2023 on blood samples of 10 CLL patients from the Universitas Academic Hospital Haematology Clinic in Bloemfontein, South Africa. Samples were stored at room and refrigerator temperatures and analysed at baseline, 24 h, 48 h, 72 h and 96 h. We recorded the percentage and intensity of antigen expression of CLL makers, including CD5, CD20, CD23, CD79b, CD200 and sIgM, and assessed whether these affected the adapted and modified Matutes scores.

Results: Statistically significant changes were observed in CD5 (p = 0.028), CD23 (p = 0.003) and CD200 (p = 0.005) expression, with better stability at refrigerator temperature. Two samples showed changes in both Matutes scores by 24 h, irrespective of storage temperature. By 48 h, scores changed to aCLL in six room-temperature and four refrigerated samples. A majority shift in diagnosis to aCLL (modified Matutes: n = 8/10; adapted Matutes: n = 7/10) was observed at 96 h for refrigerated samples.

Conclusion: These findings indicate that pre-analytical variables influence antigen stability in CLL samples, with better preservation at refrigerator temperature, recommending analysis within 48 h of collection.

What this study adds: This study highlights the impact of pre-analytical variables on the flow cytometric diagnosis of CLL. Extended room temperature storage alters antigen expression, shifting Matutes scores and potentially affecting the final diagnosis. The findings emphasise optimised sample handling, for improved diagnostic accuracy in laboratory medicine.