CLINICAL LABORATORY QUALITY-CONTROL - A COSTLY PROCESS NOW OUT OF CONTROL

We studied laboratory internal quality control (QC) processes using th e College of American Pathologists Q-Probes program. Over 500 institut ions participated, providing practices based on approximately 710 000 cholesterol, 880 000 calcium, 400 000 digoxin, and 1 180 000 hemoglobi n QC results. The costs of QC included participant median control samp le rates comprising 9.1, 9.4, 37.0, and 6.8% for the four analytes res pectively, repeat patient test rates of 0.36% for hemoglobin to 0.65% for digoxin, and median delays in reporting results when QC exceptions occurred of 15.8 min for calcium to 24.7 min for hemoglobin. Quality control practices were complex and highly variable among participants and frequently differed from internal laboratory protocols and from lo ng-established quality guidelines, We conclude that QC is costly, and laboratorians frequently do not follow established QC practices, in pa rt because they are complex. To improve compliance, we believe QC prac tices must be simplified. (C) 1997 Elsevier Science B.V.