Performance characteristics of optimized MAAs that include the LAg-Avidity assay.

Samples from the MACS, ALIVE, and HIVNET 001 cohorts (N = 1,782) and samples from the JHHCC cohort (N = 500) were tested using MAAs that included the LAg-Avidity assay (MAA #1 and MAA #2, Figure 2). The following units were used for the component assays: LAg-Avidity assay, normalized optical density units (OD-n); BioRad-Avidity assay, percentage (avidity index); viral load, copies/mL; CD4 cell count, cells/mm3. Samples were classified as MAA positive if they met the criteria for all of the assays in the MAA (Figure 2). The number and percentage of samples that were MAA positive are presented separately for individuals with different durations of HIV infection (see Methods). N indicates the number of samples in each group. The following additional performance measures are shown: mean window period, shadow, relative sample size needed for cross-sectional surveys (with MAA #2 as a reference), relative cost, and relative cost adjusted for the mean window period (with MAA #2 as a reference) (see Methods). The cost analyses assumed that assays would be performed in the order shown.