Serum xylose analysis by gas chromatography/mass spectrometry.
A gas chromatography/mass spectrometric (GC/MS) isotope dilution assay for xylose was developed using tertbutyldimethylsilyl-derivatized xylose and [13C]1xylose, and applied to human serum samples. A calibration curve in serum using this assay showed < 3% variation (< 10 mg/L) for any given point. The correlation coefficient for xylose measurements made on 27 sera between a colorimetric method performed by a national commercial reference laboratory and the GC/MS method developed here was .952. However, xylose determinations of 10 of 27 samples differed by > 10% (up to 150 mg/L) when colorimetric values were compared to GC/MS. Two of these samples had borderline-low xylose values by GC/MS, but were well within the normal range by colorimetric analysis. gas chromatography/mass spectrometric isotope dilution assay appears to be an accurate method to measure xylose in serum. These data also suggest that further prospective studies comparing GC/MS to colorimetric methods are indicated for subjects undergoing oral xylose testing.
Deutsch
J C
JC
Division of Gastroenterology, University of Colorado Health Sciences Center, Denver 80262.
Kolli
V R
VR
Santhosh-Kumar
C R
CR
Kolhouse
J F
JF
D003124:Colorimetry / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D015394:Molecular Structure; D012680:Sensitivity and Specificity; D014994:Xylose / Q000097:blood* / Q000737:chemistry
D014994:Xylose