African Journal of Laboratory Medicine最新文献

Background: Parathyroid hormone (PTH) measurement is key for diagnosing parathyroid disorders, and for management of chronic kidney disease. Available PTH assays include second (intact PTH) and third (PTH 1-84) generations. Data comparing interchangeable use are insufficient.

Objective: The objective of this study was to compare intact and 1-84 PTH assays to determine the difference in analytical performance and impact on clinical interpretation.

Methods: A method comparison was done on residual samples with PTH requests (06 April 2022 - 21 September 2022) from a tertiary hospital in South Africa. Parathyroid hormone was measured using both intact PTH and 1-84 PTH assays. Clinical performance was compared in the diagnosis of hypo- and hyperparathyroidism, and in pre-dialysis and dialysis chronic kidney disease patients.

Results: Among 481 samples, intact PTH had a higher median concentration than PTH 1-84 (9.85 pmol/L vs. 8.51 pmol/L, p < 0.0001), but the two showed good correlation (r = 0.994, p < 0.0001). Regression analysis revealed systematic (intercept = 0.887 pmol/L [95% confidence interval: 0.788 - 1.005]) and proportional differences (slope = 0.713 pmol/L, [95% confidence interval: 0.703 - 0.723]), with increased deviations at higher concentrations. The average bias was 18.5%, exceeding allowable limits. Among the 276 patients (170 women, 106 men, age range: 18-89 years) included in the clinical study, interpretation was unchanged.

Conclusion: A bias was observed between the PTH assays, indicating that they should not be used interchangeably. However, no changes in clinical interpretation were observed when one assay was used over the other.

What this study adds: The study confirms the recommendation by Kidney Disease: Improving Global Outcomes for the use of assay-specific upper limit of normal instead of generic cut-off in dialysis patients. This study further highlights the need for standardisation of PTH assays.

Background: Febrile neutropaenia (FN) is an oncology emergency, but there is a paucity of data on it in Africa.

Aim: This study aimed to review and aggregate data on FN in the context of antibiotic resistance.

Methods: Published original articles between 1991 and 2024 were systematically searched in Google Scholar, PubMed, and African Journals Online databases (grey literature excluded). 'Febrile neutropenia' was combined by Boolean terms 'OR' and 'AND' with individual countries for the searched terms. Data aggregation on bacteria isolates and antibiotics was done using Microsoft Excel.

Results: Of 16 637 articles retrieved, 15 (from nine countries) with 1216 non-duplicate isolates were included in the analyses after exclusion of irrelevant and duplicate articles. There were 57.0% (698/1225) Gram-positive and 43.3% (527/1225) Gram-negative bacteria. Aggregated resistance to antibiotics for Gram-positive bacteria was 71.8% (163/227), for ampicillin, 74.3% (226/304), for cefoxitin, 64.1% (25/39), and 54.0% (47/87) for oxacillin, while that of Gram-negative bacteria was 35.5% (184/519) for ciprofloxacin, 60.6% (168/277) for ceftriaxone, 65.9% (89/135) for cefuroxime, and 38.2% (153/401) for imipenem. Staphylococcus aureus had 68.8% (22/32) resistance to oxacillin/methicillin and 10% (1/10) resistance to vancomycin. Klebsiella spp. was 50% (9/18) resistant to quinolones, 75.9% (22/29) resistant to third-generation cephalosporins, and 25.0% (4/16) resistant to carbapenems, while Acinetobacter spp. was 85.7% (6/7) resistant to gentamycin.

Conclusion: This review highlighted the paucity of data and the emergence of multidrug resistance in FN in Africa. There is a need for antibiotic-resistance surveillance and antibiotic stewardship to optimise therapy in FN in Africa.

What this study adds: To the best of our knowledge, this is the first systematic review of FN in Africa in the context of available laboratory resources across the African regions.

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.