Identification of nonanalytic issues in HIV-1 antibody testing using blind proficiency testing.

Blind proficiency testing was used to examine nonanalytic performance indicators for human immunodeficiency virus type 1 (HIV-1) antibody testing. Physician offices, clinics, and hospitals located throughout Southern California submitted simulated patient specimens to laboratories as routine test requests. A total of 32 laboratories were involved during five blind proficiency testing surveys. Turnaround time for a reactive specimen ranged from three to 17 days. Laboratory charges for evaluating a reactive specimen varied depending on the volume of testing, prevalence of reactive specimens, and whether screening and confirmatory tests were billed separately or as a package price. Charges for an enzyme immunoassay screening test plus supplemental tests ranged from $11.75 to $114.50, with a median of $31.00 for 24 laboratories that participated in one of the five surveys. Evaluation of laboratory report content revealed that 37% of the 16 screening reports and 71% of the 14 supplemental reports contained information that was unrelated to the patient results. Evaluation of the testing system documents the need to monitor multiple outcomes of the total laboratory testing process, not just the analytic testing phase.