NCEP analytic performance goals for HDL-C (26)(27).
In developing guidelines for analytical performance, the expert panel considered the requisite analytical performance needed for reliable medical decisions in relation to biological variation and the capabilities of routine laboratories [for a more detailed explanation of the goal setting process, see Refs. (26)(27)]. The current primary goal is that total error (bias + 1.96CV) be within 13% of the true value. The total error term, combining the contributions of imprecision (random error) and inaccuracy or bias (systematic error), represents the maximum tolerable error in measurement of a single specimen to 95% tolerance limits, i.e., in 19 of every 20 measurements. The underlying specifications for imprecision and bias consistent with the total error goal are informative. Imprecision, in proportional units or CV, should be ≤4%. At low HDL-C values, this proportional target becomes difficult to achieve, e.g., at 250 mg/L the proportional goal would be 10 mg/L; therefore, the precision guideline shifts to an absolute or standard deviation target of 17 mg/L for HDL-C values <420 mg/L. The bias should be <5% from the true value, determined by the accepted RM. Thus, in this example the total error target of 13% is equal to 5% plus 1.96 times 4%.