External evaluation of the quality of CD4 T cells enumeration in the laboratory of immunology and hematology at the Cocody University Hospital Center

The rate of T lymphocytes-CD4 (TLR4) is a crucial parameter for therapeutic decision and follow-up in patients with Human Immunodeficiency Virus (HIV) infection. This must be determined in a reliable and accurate way. The laboratory of immunology and hematology at the Cocody University Hospital Center has participated in the External Quality Assessment program (EQAP) for TLR4 enumeration provided by QASI (Quality Assessment and Standardization for Immunological Measures Relevant to HIV/AIDS) in order to deliver quality results. This study aims to assess laboratory performance in TLR4 enumeration. We conducted a retrospective study to evaluate the laboratory performance reports from EQAP. Performance indicators such as SDI (Standard Deviation Index) and CV (coefficient of variation) were evaluated. Program participation rate was 83.33%. Performance indicators were satisfactory. The majority of SDI were included in the confidence interval [-2; +2]. The CV of samples with normal CD4 values were within the standards. Compliance rate of CD4 results was 89.58% and 91.87% for the absolute and the relative performance respectively. The CV of samples with low CD4 rates were beyond the standards (>15%). EQAP is an indispensable tool enabling laboratory to monitor the quality of its analyses. However, corrective measures should be strengthened during the follow-up period to sustain and improve the quality of the analyses.