The lactose provocation test. An easy and cheap screening method for lactose malabsorption
Marcussen, N.; Pedersen, C.; Sørensen, S.; Wulff, H.R.
Ugeskrift for Laeger 145(18): 1372-1374
1983
ISSN/ISBN: 0041-5782 PMID: 6868165 Document Number: 204166
Patients with chronic diarrhoea or irritable bowel symptoms should be screened for lactose malabsorption. As a rule a time-consuming lactose tolerance test with blood glucose measurement is used for that purpose. To reduce the number of tolerance tests in the daily routine, a simple lactose provocation test was introduced as a screening method. The patients ingest 100 g lactose in a cup of tea in their homes. The test is considered to be positive if this results in diarrhoea, borborygmi, meteorism or colicky pain. The test results were negative in 38 of 67 patients, in whom further investigation for lactose malabsorption was avoided as it was considered that the diagnostic sensitivity of the provocation test was maximum on account of the large quantity of lactose used. The lactose tolerance test showed lactose malabsorption in only 5 patients with positive results to the provocation test. The diagnostic specificity of the provocation test is therefore low. Further analysis of the results suggests, however, that greater specificity and greater economy in the number of tolerance tests may be obtained if provocation of diarrhoea only is considered as a positive result. The prevalence of lactose malabsorptions was 8% in patients with irritable bowel symptoms.