Fig. 4

Variation estimates by runs and analysts using human serum sample S/N ratio values, excluding high CV samples, voided samples, and outliers. Box and whisker plot of 25th and 75th percentiles, median, minimum, and maximum is presented. Analyst 1 = (Q3 + 1.5 × interquartile); analyst 2 = (Q3 + 1.5 × interquartile). a Estimation of variation between runs. b Estimation of variation between analysts. c Estimation of variation between analysts and runs. CV, coefficient of variation; DF Den, denominator degree of freedom; DF Num, numerator degree of freedom; ECL, electrochemiluminescence; Prob, probability S/N, signal to noise