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It is an enzymatic kit to measure xylose that can be used together with LacTEST in the diagnosis of hypolactasia. It has been developed by Venter Pharma S.L. and validated in automated equipments for clinical analyses.

Xylossay , the enzymatic kit for xylose quantification is available for 11 and 22 mL and includes the following reagents:

  • Vial 1: Phosphate buffer 50 mM, pH 8.0 (solution)
  • Vial 2: Lyophilized NAD+
  • Vial 3: Lyophilized Xylose dehydrogenase enzyme
  • Vial 4:Calibrator: Standard xylose solution (3.75 mg/dl)



The kit is manufactured by Immunostep S.L.

It can be incorporated to automated equipment of analysis such as Cobas 501 and 502 (Roche), Dimension Vista 1500 (Siemens) and ILab 600 and 650 (Werfen).

The whole application for different systems can be seen/downloaded in the following links.

cobas dimension werfen

Note: if you have an equipment different from these ones and you wish to incorporate it,please contact us.

Xylossay is used for the measure of xylose in urine. It is highly specific and precise. It has been validated to make xylose measurement in patient´s urine previouly ingestion of LacTEST 0.45g for the diagnosis of hypolactasia. It has been included in LacTEST 0.45g Summary of Product Characteristics.

Once LacTEST 0.45g has been dissolved in water and ingested after a fasting period,urine must be collected during the next 5h. Urine volume will be measured and a sample will be analized in an automated equipment using Xylossay. The analyzer will calculate xylose concentration in the sample and will multiply it by the total volume of urine expressing the result as mg of xylose.

If you do not have the calculations incorporated into your system you can use this worksheet (click here).

The development of Xylossay to be used with LacTEST has followed a whole validation process. The proof of concept was carried out in plates and cuvettes. Finally the method was validated in automated equipments and a study of concordance was performed with the previous method authorized. Very good results were obtained allowing its inclusion in LacTEST Summary of Product Characteristics.

Sánchez-Moreno I, García-Junceda E, Hermida C, Fernández-Mayoralas A. Development of a new method for d-xylose detection and quantification in urine, based on the use of recombinant xylose dehydrogenase from Caulobacter crescentus. J Biotechnol 2016;234:50-7.