Quality control of the total lymphocyte count parameter obtained from routine haematology analyzers, and its relevance in HIV management.

Abstract

Lymphocyte subs /CD4 T Helper cell enumeration in HIV care and treatment in resource constrained settings can be difficult to ascertain as a result of the lack of the necessary instrumentation, capacity and infrastructure. However, it is imperative to gain such information for patient monitoring in HIV. The Total Lymphocyte Count (TLC) is useful as a surrogate marker for CD4 count as recommended by the World Health Organization (WHO) and to calculate CD4% for paediatric use. This study therefore sets out to determine and compare the accuracy of the total lymphocyte counts obtained from three haematology analyzers designated A, B and C. that arc in regular use for routine haematological parameters at the main referral hospital in Barbados. West Indies. The TLC of 263 HIV treatment naive individuals attending the HIV Reference Unit in Barbados were enumerated on the three haematology analyzers. The 'lymphosum' (Sum of lymphocyte subsets: T-helper cell, T-cytotoxic cells, B lymphocyte and Natural killer cells) should be equal lo the TLC, and is derived by immunophenotypic analysis on a 4-colour flowcytometer. Machine C had the highest positive correlation between the TLC and the lymphosum with and R: of 0.9031 compared to machine A with an R2 values of 0.7119 and Machine B with R2 values of 0.637.