An article published
this year in “HINDAWI BIOMED RESEARCH INTERNATIONAL” using one customized
assay developed and manufacturered by
Immunostep to Carmen Hermida from Venter Pharma, in the Analytical validation of a new enzymatic and
automatable method for D-xylose measurement in human urine samples. Congrats and Thanks.
Summary:
Hypolactasia, or intestinal lactase deficiency, affects more than half
of the world population. Currently, xylose quantification in urine after
gaxilose oral administration for the noninvasive diagnosis of hypolactasia is
performed with the hand-operated non-automatable phloroglucinol reaction. This
work demonstrates that a new enzymatic xylose quantification method, based on
the activity of xylose dehydrogenase from Caulobacter crescentus, represents an
excellent alternative to the manual phloroglucinol reaction. The new method is
automatable and facilitates the use of the gaxilose test for hypolactasia
diagnosis in the clinical practice. The analytical validation of the new
technique was performed in three different auto-analyzers, using buffer or
urine samples spiked with different xylose concentrations. For the comparison
between the phloroglucinol and the enzymatic assays, 224 urine samples of
patients to whom the gaxilose test had been prescribed were assayed by both
methods. A mean bias of -16.08 mg of xylose was observed when comparing the
results obtained by both techniques. After adjusting the cut-off of the
enzymatic method to 19.18 mg of xylose, the Kappa coefficient was found to be
0.9531, indicating an excellent level of agreement between both analytical
procedures. This new assay represents the first automatable enzymatic technique
validated for xylose quantification in urine.
Reference:
Analytical validation of a new enzymatic and
automatable method for D-xylose measurement in human urine samples
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