[Plasma concentrations of vitamin K1 and acenocoumarol related to international normalized ratios]

Reduced vitamins K are acting as cofactors of glutamic carboxylation of procoagulant factors (II, VII, IX and X). The reduction of these vitamins is inhibited by oral anticoagulants. The response to antivitamins K is individual and may change during the treatment of a patient. The determinations of plasmatic vitamin K and acenocoumarol may help to explain the mechanism of a resistance to the anticoagulant therapy. Quantifications of vitamin K1 are realized after liquid-liquid extraction with liquid chromatography and fluorescence detection after post-column reduction. For acenocoumarol, plasma concentration is measured, after liquid-liquid extraction, by liquid chromatograph, with ion trap mass spectrometer detector.