Factors Associated with Sample Rejection for CD4+/CD8+ T Cell Count Analyses at the Kenyatta National Hospital Comprehensive Care Center Laboratory, Kenya
- 1 Department of Human Pathology, Thematic Unit of Immunology, University of Nairobi, Nairobi, Kenya
- 2 Department of Human Pathology, Thematic Unit of Immunology, University of Nairobi, Nairobi, Kenya
- 3 Department of Human Pathology, Thematic Unit of Hematology and Blood Transfusion Unit, University of Nairobi, Nairobi, Kenya
Abstract
Background: The appropriate time to initiate antiretroviral therapy (ART) in HIV/AIDS patients is determined by measurement of CD4+/CD8+ T cell count. The CD4/CD8+ T cell count is also useful, together with viral load, in monitoring disease progression and effectiveness treatment regimens. Several factors may contribute to sample rejection during the CD4+/CD8+ T cells count, resulting in negative effects on patient management. Objective: Evaluate the causes for CD4+CD8+ T cell count sample rejection at the Kenyatta National Hospital Comprehensive Care Center Laboratory. Method: A retrospective cross-sectional study was conducted between 2018 and 2020. Data was obtained from the “rejected samples” for Partec R FlowCyp flow cytometry file. Designed data collection sheet was used for data capture. A total of 3972 samples were submitted for CD4+/CD8+ T cell count during the study period. Causes for sample rejection were numbered 1 to 12, each representing a reason for sample rejection. Number 1 was sub-categorized into clotted, hemolyzed, short-draw and lipemic. Data was analyzed using excel, and presented using tables, graphs and pie charts. Approval to conduct the study was obtained from KNH/UoN ERC. Results: In the study period, 81/3972 (2.0%) samples were rejected. Samples submitted more than 48 hours after collection were mostly rejected. Other factors included improper collection technique, delayed testing, patient identification error and incorrect use of vacutainer. A combination of clotted samples, specimen submission more than 48 hours caused the most frequent sample rejection, followed with combination of specimen submission more than 48 hours, delayed testing and delayed specimen processing. Together, clotted samples, incorrect vacutainer and poor specimen label caused the least sample rejection. Conclusion: Sample rejection rate for CD4/CD8+ T cell count was relatively low, and multiple factors contributed to rejection. However, improved quality assurance will enable more benefit to patients who seek this test in the laboratory.
- Ceulemans, A., Bouzahzah, C., Prat, I., Urassa, W. and Kestens, L. (2019) CD4-T Cell Enumeration in Human Immunodeficiency Virus (HIV)-Infected Patients: A Laboratory Performance Evaluation of Muse Auto CD4/CD4% System by World Health Organization Prequalification of in Vitro Diagnostics. PLoS ONE, 14, Article ID: e0209677. https://doi.org/10.1371/journal.pone.0209677
- Westerman, L.E., Kohatsu, L., Ortiz, A., McClain, B., Kaplan, J., Spira, T., et al. (2010) A Quality Management Systems Approach for CD4 Testing in Resource-Poor Settings. American Journal of Clinical Pathology, 134, 556-567. https://doi.org/10.1309/AJCPP7MCHFYLX2FM
- Gunnur Dikmen, Z., Pinar, A. and Akbiyik, F. (2015) Specimen Rejection in Laboratory Medicine: Necessary for Patient Safety? Biochemia Medica, 25, 377-385. https://doi.org/10.11613/BM.2015.037
- Plebani, M. (2012) Quality Indicators to Detect Preanalytical Errors in Laboratory Testing. Clinical Biochemist Reviews, 33, 85-88.
- Shiferaw, M.B., Yismaw, G. and Getachew, H. (2018) Specimen Rejections among Referred Specimens through Referral Network to the Amhara Public Health Institute for Laboratory Testing, Bahir Dar, Ethiopia. BMC Research Notes, 11, Article No. 781. https://doi.org/10.1186/s13104-018-3891-7
- Carraro, P. and Plebani, M. (2007) Errors in a Stat Laboratory: Types and Frequency 10 Years Later. Clinical Chemistry, 53, 1338-1342. https://doi.org/10.1373/clinchem.2007.088344
- International Organization for Standardization (2012) ISO 15189:2012: Medical Laboratories: Particular Requirements for Quality and Competence. International Organization for Standardization, Geneva.
- Adan, A., Alizada, G., Kiraz, Y., Baran, Y.N.A. (2017) Flow Cytometry: Basic Principles and Applications. Critical Reviews in Biotechnology, 37, 163-176. https://doi.org/10.3109/07388551.2015.1128876
- Peter, T., Badrichani, A., Wu, E., Freeman, R., Ncube, B., Ariki, F., et al. (2008) Challenges in Implementing CD4 Testing in Resource-Limited Settings. Cytometry Part B: Clinical Cytometry, 74B, S123-S130. https://doi.org/10.1002/cyto.b.20416
- Andrew, C. and Robyn Richardson, Z.L. (2019) Success and Failure of Initial Antiretroviral Therapy in Adults: An Updated Systematic Review. AIDS, 33, 443-453. https://doi.org/10.1097/QAD.0000000000002077
- Kihara, H.J. (2010) Needs Assessment for Strengthening Laboratory Human Resources Capacity for Universal Access to HIV, Malaria and TB Services in Three Sub-Saharan Countries WHO Library Cataloguing-in-Publication Data. World Health Organization, Geneva.