Equis ISSN 2398-2977

Gastrointestinal: intestinal function tests

Synonym(s): Intestine function tests

Contributor(s): Graham Munroe, Prof Jonathon Naylor

Introduction

  • These tests assess the efficiency of sugars/starch absorption from the intestinal lumen and are used in the diagnosis of intestinal malabsorption and intolerance   Gastrointestinal: small intestine - malabsorption  .
  • The common tests used are:
    • Oral glucose absorption test.
    • D(+)-Xylose absorption test.
    • Starch tolerance test.
    • Oral lactose tolerance test.

Uses

  • Loss of weight despite normal feeding/nutritional parameters, as well as ruling out other non-digestive problems, suggests a malabsorption syndrome.

Oral glucose absorption test

D(+)-Xylose absorption test

  • Assessment of small intestine absorption similar to the oral glucose absorption test.

Starch tolerance test

  • Assessment of small intestine absorption and pancreatic exocrine function.

Oral lactose tolerance test

  • Specific assessment of lactose absorption/tolerance in suckling foals.

Advantages

  • Non-invasive.
  • Oral glucose absorption test: inexpensive, easy to perform.

Disadvantages

  • As glucose is subject to metabolism during the test on theoretical grounds xylose is the preferred carbohydrate.
  • Glucose/xylose absorption test is not specific for any one particular malabsorption syndrome not definitively diagnostic.
  • Xylose absorption test is expensive; xylose measurement is not commonly available at commercial labs; influenced by various other factors, eg intestinal transit time and rate of gastric emptying, bacterial intralumenal overgrowth, energy content of the diet.
  • Lactose tolerance test should only be performed in foals. Lactose may produce mild colic and diarrhea in mature horses.

Requirements

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Preparation

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Procedure

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Aftercare

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Cummings J F, de Lahunta A, Mohammed H O, Divers T J, Valentine B, Summers B A & Cooper B J (1991) Equine Motor Neuron Disease - a new neurologic disorder. Equine Pract 13 (9), 15-18 PubMed.
  • Mair T S, Hillyer M H, Taylor F G & Pearson G R (1991) Small intestinal malabsorption in the horse: an assessment of the specificity of the oral glucose tolerance test. Equine Vet J 23, 344-346 PubMed.
  • Lindberg R, Persson S G B, Jones B, Thoren-Tolling K & Ederoth M (1985)  Clinical and pathophysiologic features of granulomatous enteritis and eosinophilic granulomatosis in the horse. Zentralblatt Veteriner Medizin A 32 (7), 526-539 PubMed.
  • Martens R J, Malone P S & Brust D M (1985) Oral lactose tolerance test in foals: technique and normal values. Am J Vet Res 46, 2163-2165 PubMed.
  • Bolton J R et al (1976) Normal and abnormal xylose absorption in the horse. Cornell Vet 66, 183-197 PubMed.
  • Roberts M C & Pinsent P J N (1975) Malabsorption in the horse associated with alimentary lymphosarcoma. Equine Vet J 7, 166-172 PubMed.
  • Roberts M C (1974) The D(+) xylose absorption test in the horse. Equine Vet J 6, 28-30 PubMed.
  • Roberts M C & Hill F W C (1973) The oral glucose tolerance test in the horse. Equine Vet J 5, 171-173 PubMed.

Other sources of information

  • Mair T , Divers T & Ducharme N (2002) EdsManual of Equine Gastroenterology.W B Saunders. ISBN: 0702024864.
  • Colahan P T, Mayhew I G, Merritt A M & Moore J N (1999) EdsEquine Medicine and Surgery.5th edn. Mosby.


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