A re-evaluation of the D (+) xylose absorption test in the horse.

The study revisits the effectiveness of the D (+) xylose absorption test in horses for diagnosing small intestinal disorders. It compares different assay methods, evaluates the effect of an anticoagulant agent, and determines an optimal xylose dosage and sample collection period.

D (+) Xylose Absorption Test

• This research studies the D (+) xylose absorption test, which is a diagnostic tool used in the investigation of small intestinal disorders in horses.
• The test is based on the horse’s ability to absorb d-xylose, a sugar, which varies depending on the health condition of the small intestine. In healthy horses, the sugar will be effectively absorbed and then excreted in the urine.

Comparison of Assay Methods

• Three different assay methods were compared in the study: the parabromoaniline (PBA) method, the ferric chloride-orcinol (FCO) method, and the orthotoluidine method.
• The researchers found no significant differences in results between the PBA and FCO methods, making either an accurate choice for the test.
• However, the orthotoluidine method was stated as being unsatisfactory with no further details provided on why it was considered so.
• The FCO method was specifically highlighted as a preferable choice for occasional tests performed in practice.

Effect of Anticoagulant Agent and Dosage

• The study also looked into any possible effects the anticoagulant agent might have on test results and found no significant impact, suggesting that the prominence of the anticoagulant agent in the sample does not influence the d-xylose absorption.
• The researchers decided on an optimal dosage of xylose for the test. A dose of 0.5g commercial grade xylose per kilogram of body weight given as a 10% solution through a stomach tube resulted in a peak plasma xylose level after 90 minutes.
• This peak level should be able to differentiate between normal and abnormal absorption rates, proving useful in identifying potential small intestinal disorders.

Sample Collection Period

• The researchers propose that a 2-hour sample collection period would be sufficient for the test. This recommendation likely takes into account the 90-minute peak level of plasma xylose after dosage administration.