TABLE 1.

Intra- and inter-assay reproducibility for the quantitation of VK catabolite concentrations in human urine by LC-MS/MS

	Intra-Assay Reproducibility (Sample A, n = 11)			Inter-Assay Reproducibility (Sample B, n = 48)
	K Acid I	K Acid II	MK1 ω-COOH	K Acid I	K Acid II	MK1 ω-COOH
Mean (pmol/ml)	1.40	4.37	0.065	1.35	2.59	0.045
SEM (pmol/ml)	0.04	0.08	0.003	0.02	0.03	0.001
Coefficient of. variation (%)	8.4	6.4	16.2	11.0	7.8	12.0

Samples A and B represent two separate urine samples, collected roughly 6 months apart from the same healthy adult male subject. Concentrations are listed in picomoles of metabolite per milliliter of urine. Inter-assay reproducibility was assessed through four identical experiments conducted over a month-long period.