Inter-assay precision of FACSCount, CyFlow Counter and Pima CD4.

<p>N means Number of replicates; CV means Coefficient of Variation; SD means absolute standard deviation (presented for low CD4 only); Low means CD4 lower than 200 cells/mm3; Medium means CD4 between 300 and 500 cells/mm3; and High means CD4 greater than 500 cells/mm3.