Selection of anticoagulants for lymphocyte immunophenotyping. Effect of specimen age on results.

In a multi-center study, whole blood specimens from 31 HIV-positive and 43 HIV-negative donors were collected in three different anticoagulants and assayed for lymphocyte subsets fresh (within 6 h), and 1 and 2 days later. Each center prepared the specimens by their routine whole blood lysis procedure, labeling with a recommended panel of two-color monoclonal antibody combinations. 1 day (up to about 30 h) after blood collection, the results obtained from blood collected in EDTA (ethylenediamine tetra-acetate), ACD (acid citrate dextrose), and heparin were similar to fresh. Up to 48 h, only ACD and heparin, not EDTA, yielded results similar to fresh specimens. These results were similar for both HIV-positive and -negative specimens.