Analytic clinical laboratory precision--state of the art for thirty-one analysis.

Relationships of concentration and coefficients of variation for 31 clinical laboratory analytes are described. Estimated mean regression curves and standard deviations of individual laboratory coefficients of variation about the mean regression are calculated. Most analytes showed a significant relationship between concentration and coefficient of variation. State-of-the-art precision is compared with medical goals. The relationship of precision performance standards to the state-of-the-art precision, statistical outliers, and laboratory error is discussed. Statistically significant trends of improving analytic precision are observed for most analytes in both manual and automated methods.