STATISTICAL QUALITY-CONTROL OF HIV-1 ELISA TEST-PERFORMANCE

Ensuring the quality and performance of human immunodeficiency virus, type 1 (HIV-1) enzyme-linked immunosorbent assay (ELISA) testing in ro utine laboratory situations is an important practical concern. In this article we develop statistical quality control procedures designed to monitor test performance of the microplates being processed. First, t he logarithm of measured optical density is shown to be a more appropr iate scale on which to work. Shewhart control charts are considered bu t are not entirely satisfactory because of between-plate variation. Co rrect classification depends more on within-plate variation than on be tween-plate variation. Range charts are useful, but they do not direct ly indicate whether the results from any particular microplate are rel iable. Consequently, a new statistical control chart-the separation ch art-is proposed, and the assumptions on which it is based are empirica lly verified. Retrospective analysis of nearly 1,300 microplates, usin g separation and range charts, demonstrates that these statistical pro cess control methods may represent a potentially useful supplement to the manufacturer's recommended quality control procedures.