Correlation between symptoms developed after the oral ingestion of 50g lactose and results of hydrogen breath testing for lactose intolerance. [Aliment Pharmacol Ther] Journal article

Background: Lactase deficiency is a common condition responsible for various abdominal symptoms. Lactose hydrogen breath test (H2-BT) is currently the gold standard in diagnosing lactose intolerance. Aim: Assessing sensitivity and specificity of symptoms developed after oral lactose challenge.
Methods: Intensity of nausea, abdominal pain, borborygmi, bloating and diarrhea was recorded every 15 minutes up to 3 hours after ingestion of 50g lactose in patients with positive (i.e. breath H2-concentration >/=20 ppm above baseline) and negative lactose H2-BT.
Results: Between July 1999 and December 2005 1127 patients (72% females) underwent lactose H2-BT A positive result was found in 376 (33%). Sensitivity of individual symptoms ranged from 39% (diarrhea) to 70% (bloating) while specificity ranged from 69% (bloating) and 90% (diarrhea). A positive H2-BT was found in 21% of patients with one symptom, 40% of patients with 2 symptoms, 44% of patients with 3 symptoms, 67% of patients with 4 symptoms and 82% of patients with 5 symptoms. Symptom intensity was significantly higher for each symptom in the positive group.
Conclusion: Evaluating symptoms developed after ingestion of 50g lactose can be used as a simple screening test to select patients that need to be referred for lactose intolerance testing.

Aliment Pharmacol Ther