The detection of problem analytes in a single proficiency test challenge in the absence of the Health Care Financing Administration rule violations

The Clinical Laboratory Improvement Act of 1988 (CLIA 88) has dramatically changed proficiency testing (PT) practices having mandated (1) satisfactory PT for certain analytes as a condition of laboratory operation, (2) fixed PT limits for many of these «regulated» analytes, and (3) an increased number of PT specimens (n=5) for each testing cycle. For many of these analytes, the fixed limits are much broader than the previously employed Standard Deviation Index (SDI) criteria. Paradoxically, there may be less incentive to identify and evaluate analytically significant outliers to improve the analytical process. Previously described «control rules» to evaluate these PT results are unworkable as they consider only two or three results