Utility of absolute lymphocyte count for the monitoring of AIDS patients

Abstract

Background and objectiveCD4 count for monitoring of AIDS patients may not be available in resource poor setting. To compare Absolute lymphocyte count (ALC) and CD4 count in AIDS patients and to evaluate the use of ALC as a surrogate marker for CD4 count in monitoring AIDS patients. Materials & methodsTwo anticoagulated EDTA whole blood samples – one for CD4 count through flowcytometry and other to perform ALC were collected from 1000 HIV infected individuals who attended ART at St. John's medical college hospital, Bangalore. Both CD4 count and ALC were correlated to predict positive and negative predictive values, sensitivity and specificity. ResultsALC cut-off of 1646/μl correlated with CD4 count ≤200/μl with PPV 79.48%, and specificity 95.47%. ALC of 2009/μl correlated with CD4 count ≤350/μl with PPV 74.94% and specificity 82.28%. ConclusionsThis study showed an optimum cut-off value for ALC correlated with CD4 count ≤200/μl to be 1646/μl and with CD4 count ≤350 was 2009/μl. This is quite high compared to the WHO guideline of ALC of 1200/μl. A higher cut-off of ALC may help to reduce failure rate by identifying patients who might benefit from ART prophylaxis. The sensitivity of ALC of 2009/μl correlating CD4 count ≤350/μl was higher than ALC of 1646/μl correlating with CD4 count ≤200/μl. Therefore ALC can be used as a surrogate for CD4 counts as a screening test to initiate and monitor ART for HIV patients in resource poor setting.