FIG. 2.

Summary (means and standard deviations) of viabilities (A) and viable yields (B) of PBMC prepared by the participating laboratories in each QAP round (yield data were calculated with the maximum yield being 100%). The ratio of new to total labs participating in each round is indicated. Initiatives to improve performance are indicated by arrows. The dashed lines represent the performance standards set for both viability and yield. Local donor results represent PBMC collected from an HIV-negative donor at the laboratory site.