The significance of lowered jejunal disaccharidase levels.

Disaccharidase estimations on 115 consecutive jejunal biopsies are reported. The patients were divided into four groups: 1. Normal jejunal biopsy light microscopy, not milk intolerant, 82 cases. 2. Normal jejunal biopsy light microscopy, milk intolerant, eight cases. 3. Patients with giardiasis, 11 cases. 4. Coeliac disease patients, 14 cases. The lowest disaccharidase levels were found in coeliac disease, with giardiasis cases showing intermediate levels. Poor correlation of lactase levels with milk intolerance was found. Three cases in Group 1 showing lowered lactase levels were given metronidazole and showed remission of clinical symptoms, raising the possibility that they had undiagnosed infections with Giardia lamblia.