World Journal of AIDS, 2021, 11, 181-188 https://www.scirp.org/journal/wja ISSN Online: 2160-8822 ISSN Print: 2160-8814 DOI: 10.4236/wja.2021.114013 Dec. 28, 2021 181 World Journal of AIDS Factors Associated with Sample Rejection for CD4+/CD8+ T Cell Count Analyses at the Kenyatta National Hospital Comprehensive Care Center Laboratory, Kenya Moherai Wilfred Felix 1 , Joshua Nyagol 1* , Walter Mwanda 2 1 Department of Human Pathology, Thematic Unit of Immunology, University of Nairobi, Nairobi, Kenya 2 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: Eva- luate the causes for CD4+CD8+ T cell count sample rejection at the Kenyatta National Hospital Comprehensive Care Center Laboratory. Method: A re- trospective cross-sectional study was conducted between 2018 and 2020. Data was obtained from the “rejected samples” for Partec R FlowCyp flow cytome- try 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 pre- sented 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 spe- cimen submission more than 48 hours, delayed testing and delayed specimen processing. Together, clotted samples, incorrect vacutainer and poor speci- men label caused the least sample rejection. Conclusion: Sample rejection How to cite this paper: Felix, M.W., Nya- gol, J. and Mwanda, W. (2021) Factors As- sociated with Sample Rejection for CD4+/ CD8+ T Cell Count Analyses at the Kenyatta National Hospital Comprehensive Care Cen- ter Laboratory, Kenya. World Journal of AIDS, 11, 181-188. https://doi.org/10.4236/wja.2021.114013 Received: October 20, 2021 Accepted: December 25, 2021 Published: December 28, 2021 Copyright © 2021 by author(s) and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access