Gas chromatographic–mass spectrometric determination of total homocysteine in human plasma by stable isotope dilution: method and clinical applications

The detection and quantitation of slight increases of plasma homocysteine levels is of growing interest. This has prompted us to develop a highly sensitive and accurate capillary gas chromatography–mass spectrometry (GC–MS) method. The method proved to be highly sensitive (DL=0.17 μmol/l) with between- and within-run precision less than 6% and 7%, respectively. Reference values of plasma total homocysteine have been determined for men (n=39) and women (n=36), showing a significant difference (P=0.003) between gender. Preliminary results in cerebrovascular accidents and in venous thrombosis are presented.