To achieve accuracy and reproducibility of laboratory based testing, both internal and external quality control measures are essential.8,9,12 Since 1996, the National Laboratory for HIV Immunology from the Public Health Agency of Canada has been providing the Quality Assessment and Standardization programme for Immunological measures relevant to HIV/AIDS (QASI) in an effort to assist resource-limited regions with CD4 testing.13 Currently over 1400 laboratories from more than 50 countries are enrolled and actively participating in QASI. Here, CD4 is linked to AIDS.