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Method for the Determination of Total Homocysteine in Plasma and Urine by Stable Isotope Dilution and Electrospray Tandem Mass Spectrometry by Magera, Mark J; Lacey, Jean M; Casetta, Bruno; Rinaldo, Piero is a Medicine article available to read on EtoBox.

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## Abstract Background: Total homocysteine (tHcy) has emerged as an important independent risk factor for cardiovascular disease. Analytical methods are needed to accommodate the high testing volumes for tHcy and provide rapid turnaround. Methods: We developed liquid chromatography electrospray tandem mass spectrometry (LC-MS/MS) method based on the analysis of 100 μL of either plasma or urine with homocystine-d8 (2 nmol) added as internal standard. After sample reduction and deproteinization, the analysis was performed in the multiple reaction monitoring mode in which tHcy and Hcy-d4 were detected through the transition from the precursor to the product ion (m/z 136 to m/z 90 and m/z 140 to m/z 94, respectively). The retention time of tHcy and Hcy-d4 was 1.5 min in a 2.5-min analysis. Results: Daily calibrations between 2.5 and 60 μmol/L exhibited consistent linearity and reproducibility. At a plasma concentration of 0.8 μmol/L, the signal-to-noise ratio for tHcy was 17:1. The regression equation for the comparison between our previous HPLC method (y) and the LC-MS/MS method (x) was y = 1.097x − 1.377 (r = 0.975; Sy|x =1.595 μmol/L; n = 367), and for comparison between a fluoresce

Who reads Method for the Determination of Total Homocysteine in Plasma and Urine by Stable Isotope Dilution and Electrospray Tandem Mass Spectrometry?

Author

Magera, Mark J; Lacey, Jean M; Casetta, Bruno; Rinaldo, Piero

Publisher

American Association for Clinical Chemistry; American Association for Clinical Chemistry, Inc.; Oxford University Press (OUP); American Association for Clinical Chemistry (AACC); Test accounts (ISSN 0009-9147)

Published

1999

Language

EN

Field

Medicine (Health Sciences)