This degree of carboxylation is measured in a variety of ways. Some methods depend on the Gla residue affinity to hydroxyapatite and barium sulfate. Also, ucOC should be expressed as a percentage of the total OC, which will eliminate effects of sex and age on the results. 5 Diurnal variations are important when collecting samples since it has been shown that OC concentrations are high at night and early morning while lower during late morning and afternoon. Test kits for OC are time consuming and there is wide variation between methods.
Standardization is essential when comparing data from various kits.
8 Mary Grosch is assistant professor at Northern Illinois University, DeKalb. Role of vitamin K in bone metabolism. Effects of vitamin K on bone mass and bone metabolism. An analysis of methods for determination of undercarboxylated osteocalcin. Comparison of biochemical indexes for assessing vitamin K nutritional status in a healthy adult population.