Table 1

Analytical Parameters

Before polishing data

After polishing data

Range, median CVs for 66 variables



Range, mean CVs for 66 variables



Median CV for all 66 variables



Mean CV for all 66 variables



By 13 Pairs, overall median CV



"Before polishing data", primary (raw) analysis; "After polishing data", final analysis after manual re-inspection (see text). The most critical data are the median coefficients of variation (CV); our median CV was ~10%, well within the levels necessary to conduct the proposed study. We also note that upon re-examination of the dataset for quality control purposes, 1% (11 peaks) was left unscored due to analytical concerns, and 3% (25 peaks) had scores that differed by >10% from the original call. These data suggest that, even in the absence of any optimization, we can consistently measure >96% of all metabolites with a median ± 10% precision. For the last line "By 13 pairs", we first determined the median CV for all 66 variables in each of the pairs, and then determined the mean/median of these values. By definition, overall mean CVs are unchanged by this difference in calculation procedure, and are not shown.

Shurubor et al. BMC Clinical Pathology 2007 7:9   doi:10.1186/1472-6890-7-9

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