Absolute CD4 counts obtained by a three-color flow-cytometric method without the use of a hematology analyzer.

We evaluated the Ortho TRIO-Cytoronabsolute system for determining absolute CD4 counts. The CD4 counts in our blood specimens from 100 individuals ranged from 3 to 1,962; the percent CD4 ranged from 1.3 to 62.2, respectively. The TRIO system was biased toward lower absolute counts than a combination of flow cytometry and hematology but showed no bias in percent CD4 calculations.