Table 1.

Sample stability in the fridge

Sample stability—in the fridge, sample protected from light (4‐8°C)
Period	MK‐4 (ng/mL)	K1( )(ng/mL)	MK‐7 (ng/mL)
Original value	1.004	1.051	1.320
After 2 d	0.864	1.029	1.242
After 5 d	0.658	0.927	1.131
After 7 d	0.486	0.874	1.016