Figure 4From: Method for simultaneous analysis of eight analogues of vitamin D using liquid chromatography tandem mass spectrometryComparison of 25OHD concentration levels obtained using the new assay (blue) and ALTM (grey). Bars for new assay represent SEM of duplicate measures. Bars on ALTM represent CV = 30.0 and denote the lower and upper limit of satisfactory performance [http://www.deqas.org].Back to article page