HIGH-RESOLUTION H-1-NMR SPECTROSCOPY OF BLOOD-PLASMA FOR METABOLIC STUDIES

Although spin-echo techniques are often used to obtain H-1-NMR spectra of serum or plasma samples, they do not provide reliable quantitative analyses of metabolites. We present a standardized procedure, optimiz ed for sensitivity, for using single-pulse H-1-NMR spectroscopy to ana lyze deproteinized plasma. The detection limit for various metabolites ranges between 2 and 40 mu mol/L. The method allows quantitative anal ysis of many compounds of interest in studies of inborn errors of meta bolism, including betaine and dimethylglycine, which cannot be measure d easily with other techniques. For lactate, tyrosine, threonine, and alanine, we obtained results that correlated well with those obtained by established techniques. We also present a library containing resona nce positions of 38 compounds occurring in plasma samples in health an d disease, including 14 as-yet-unidentified resonances. As an example of the diagnostic power of the technique we show a spectrum of a plasm a sample from a patient with 5-oxoprolinuria (pyroglutamic aciduria; M cKusick 266130), an enzymatic defect in glutathione biosynthesis.