Direct passive hemagglutination test for rapid quantification of plasma load of the <i>Human Immunodeficiency Virus</i>

Abstract

An inexpensive and rapid test for determining titers of Human Immunodeficiency Virus (HIV) in plasmas was developed. Washed sheep red blood cells were applied onto HIV positive plasmas, in V-bottomed microtiter plates, to complement the HIV antigens and antibodies present in plasmas. The setup was incubated for 30 minutes at 37℃. Reciprocal of the highest dilution of each plasma which gave passive agglutination of the RBCs was re ad as its HIV titer. Mean HIV load of five samples, was ≥ 4096.00 ± 0.00 after one day of storage at 4℃ but it reduced to 256.00 ± 70.10, 28.80 ± 3.20, 7.20 ± 0.80 and 1.60 ± 0.98 on days 2, 3, 4 and 7, respectively. HIV antibodies were still detectable, by ELISA, in plasma dilutions that were tested negative with the new test. It was concluded that when HIV antibodies have been confirmed, or added to plasmas, passive hemagglutination test can be applied to assess their viral loads.