Quality of laboratory performance in testing for human immunodeficiency virus type 1 antibody. Identification of variables associated with laboratory performance.

To identify factors that may affect the quality of laboratory performance of human immunodeficiency virus type 1 (HIV-1) antibody testing, the Centers for Disease Control and Prevention Model Performance Evaluation Program surveyed laboratories in 1989 that performed enzyme immunoassay (EIA) and Western blot tests for HIV-1 antibody. Panels of 10 HIV-1-antibody-positive and antibody-negative plasma samples, some of which were duplicates, were mailed to program-participating laboratories. Laboratories were also mailed survey questionnaires to ascertain their laboratory characteristics and testing practices. Using 1988 data, researchers previously found that the overall analytic performance of laboratories performing HIV-1 antibody testing was independently associated with the following: (1) requiring a minimum degree of testing personnel; (2) having written criteria for identifying unsatisfactory specimens; (3) requiring in-house training for testing personnel; (4) having tested more than 10,000 specimens; (5) being identified as an "other" laboratory type; (6) having more than 24 months of testing experience; (7) laboratory uses specific (Abbott) materials for EIA; and (8) testing specimens collected by family-planning clinics. To verify these findings, we performed multivariate analysis on 1989 performance data. For the 1989 EIA analytic sensitivity, significant positive (P < or = .05) associations were detected with having written criteria for identifying unsatisfactory specimens and with having tested more than 10,000 specimens. For the 1989 overall EIA analytic performance, a significant negative (P < or = .05) association was found with using specific (Abbott) EIA materials, and a significant positive (P < or = .05) association was found with having tested more than 10,000 specimens. For Western blot results, the only significant (P < or = .05) associations were for both analytic sensitivity and overall analytic performance and having tested more than 10,000 specimens.