Improvement and validation of d-xylose determination in urine and serum as a new tool for the noninvasive evaluation of lactase activity in humans.
J Clin Lab Anal
; 28(6): 478-86, 2014 Nov.
Article
em En
| MEDLINE
| ID: mdl-24659338
ABSTRACT
BACKGROUND:
The phloroglucinol assay is the current method for d-xylose determination in urine/plasma/serum. However, its sensitivity is limited when low amounts of d-xylose are to be measured, such as in the noninvasive evaluation of intestinal lactase with 4-galactosylxylose (gaxilose). An improved assay was therefore needed.METHODS:
We developed and validated a modified version of the phloroglucinol-based assay for quantification of d-xylose in urine/serum samples. A method for gaxilose determination by gas chromatography (GC) was also optimized.RESULTS:
Linearity ranged from 0.125 to 5.0 mg/l (5-200 mg/l in original sample). Accuracy at LOQ (0.125 mg/l) was 0.97/2.49% in spiked urine/serum; for other quality controls (QC), it was <1.27%. Intra- and interassay precision at LOQ were 6.02% and 6.45% for urine, and 8.86% and 10.00%, respectively, for serum; for other QC, precision was <2.15%. Linearity of gaxilose determination by GC was 3.90-195.17 for urine and 9.75-195.17 mg/l for serum with acceptable sensitivity and reproducibility. The method proved adequate for the d-xylose determination in healthy and hypolactasic subjects after oral administration of gaxilose.CONCLUSIONS:
The modified method provides high sensitivity and robustness for d-xylose quantification in urine/serum for routine clinical use especially in the noninvasive diagnosis of intestinal lactase deficiency with the gaxilose test.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Xilose
/
Colorimetria
/
Lactase
/
Dissacarídeos
Tipo de estudo:
Diagnostic_studies
Limite:
Humans
Idioma:
En
Revista:
J Clin Lab Anal
Ano de publicação:
2014
Tipo de documento:
Article