EVALUATION OF ALTERNATIVE CD4 TECHNOLOGIES FOR THE ENUMERATION OF CD4LYMPHOCYTES

Enumeration of CD4(+) T cells from persons infected with the human imm unodeficiency virus (HIV) is important, Traditionally this measurement has been calculated by multiplying the percent of lymphocytes that ar e CD4(+) T cells (from flow cytometry) and the number of lymphocytes p er mu 1 of blood (from hematology measures). Recently, several manufac turers have developed new techniques for determining absolute numbers of CD4(+) and CD8(+) cells without the need for the flow cytometer and hematology analyzer. We evaluated these methods for accuracy (compari son with traditional methodology) and precision (variability of replic ate determinations) as well as for use with specimens older than 1 day . Precision of the assays as determined by the coefficients of variati on (CV) from replicates varied from about 3% to about 12%, depending o n the assay and the HIV status of the patient. Correlation coefficient s of test method results with the standard methodology (r) were all gr eater than 0.9, and in most cases slopes were close to 1.0 for both CD 4 and CD8. Though each methodology will meet different requirements in the laboratory, our results indicate that these assays are all accept able for enumerating CD4 and CD8 cells in HIV+ as well as HIV- patient s.