Table 1

Analytical Parameters

Before polishing data

After polishing data


Range, median CVs for 66 variables

2–54%

2–36%

Range, mean CVs for 66 variables

2–58%

3–39%

Median CV for all 66 variables

12%

12%

Mean CV for all 66 variables

19%

17%

By 13 Pairs, overall median CV

9%

9%


"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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