Correct Use of Percent Coefficient of Variation (%CV) Formula for Log-Transformed Data

Abstract

For example, Hatzakis et al. [1], Table 1, showed an assessment of inter-instrument, inter-operator, inter-day, inter-run, intra-run and total variability of the Aptima HIV-1 Quant Dx in various HIV1 RNA concentrations. In Table 1, below, we recreate their total SD and %CV columns (the latter for which they use Formula (1), and calculate the correct log-normal %CV from Formula (7) below. From the Table 1, it can be seen that using the incorrect %CV formula for lognormally distributed data will give abnormally smaller %CVs. Volume 6 Issue 4 2017