A comparison between lactose breath test and quick test on duodenal biopsies for diagnosing lactase deficiency in patients with self-reported lactose intolerance

J Clin Gastroenterol. 2013 Feb;47(2):148-52. doi: 10.1097/MCG.0b013e31824e9132.

Abstract

Background: A lactose breath test (LBT) is usually used to diagnose lactase deficiency, and a lactose quick test (LQT) has been proposed as a new test on duodenal biopsies to detect this disorder.

Goals: We aimed to assess the diagnostic accuracy of LBT and LQT and their ability to predict the clinical response to a lactose-free diet in patients with self-reported lactose intolerance.

Study: Fifty-five patients (age 47 ± 14 y; M/F 15/36) underwent upper gastrointestinal endoscopy and 25g-LBT. Two duodenal biopsies were taken to determine lactase deficiency (normal, mild, or severe) by LQT and to rule out other causes of secondary lactose malabsorption. Patients with a positive LBT and normal LQT also underwent a glucose breath test to exclude small intestinal bacterial overgrowth as a cause of the former result. The severity of gastrointestinal symptoms was measured with a GSS questionnaire, under basal condition and 1 month after a lactose-free diet.

Results: Lactose malabsorption was detected in 31/51 patients with LBT and in 37/51 patients with LQT (P = NS). Celiac disease was found in 2 patients. Two LBT+ patients showed a positive glucose breath test for small intestinal bacterial overgrowth. Eight patients had a mild hypolactasia by LQT and a negative LBT, but they had a significant improvement of symptoms after diet. LQT and LBT were concordant in 83% of cases and predicted the response to a lactose-free diet in 98% and 81% of the cases, respectively (P = 0.03).

Conclusions: LQT is as sensitive as LBT in detecting lactase deficiency; however, it seems to be more accurate than LBT in predicting the clinical response to a lactose-free diet.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Biomarkers / metabolism
  • Biopsy*
  • Breath Tests*
  • Diet, Carbohydrate-Restricted
  • Duodenum / pathology*
  • Endoscopy, Gastrointestinal
  • Female
  • Humans
  • Lactase / deficiency
  • Lactose / metabolism*
  • Lactose Intolerance / diagnosis*
  • Lactose Intolerance / diet therapy
  • Lactose Intolerance / enzymology
  • Lactose Intolerance / pathology
  • Lactose Tolerance Test
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Prospective Studies
  • Self Report*
  • Sensitivity and Specificity
  • Severity of Illness Index
  • Surveys and Questionnaires
  • Treatment Outcome

Substances

  • Biomarkers
  • Lactase
  • Lactose

Supplementary concepts

  • Lactose Intolerance, Adult Type