Lactose malabsorption: use of breath hydrogen test and serum glucose analyses in diagnostics

Abstract

Background: The incidence of lactose intolerance in Finnish population is about 17%. Use of milk and milk products is common in Finland. Thus, lactose malabsorption and symptoms caused by it are familiar in outpatient clinic. Lactose absorption tests, determinations of breath hydrogen excretion and serum glucose concentration are used to detect lactose malabsorpuon after mgesnon of 50g lactose. Aims: To compare results of breath hydrogen test and serum glucose analysis in detection of lactose malabsorption. Patients: 36 patients with abdominal symptoms participated the study. Methods: Patients in fasting state ingested 50g of lactose colored with carmine red. Blood glucose was analyzed at baseline, and 20 and 40 min after its ingestion. A rise of blood glucose less than 1.1 mmollL was the limit value of an abnormal result, a rise 1.1-1.6 mmollL was considered as a borderline value. Breath hydrogen was determined with Micro H2analysator (Micro Medical Ltd.) at baseline, and 30, 60, 90 and 120 min after ingestion of lactose liquid. Exhaled hydrogen over 20ppm was determmed as posittve for lactose malabsorption. Patients' symptoms (bloating, flatulence, abdominal pain, nausea, diarrhea) during a period of 6 hours and lactose transit time were registered using a questionnaire. Results: In 7 patients, blood glucose rose less than 1.1 mmollL. Only 4 (57%) of these 7 patients had a positive breath test, the other 3 (43%) remained negative. In 13 patients rise of blood glucose was between 1.1 and 1.6mmollL, in I of these 13 patients (8%) the breath test was positive. The other 20 patients remained negative in the both tests. Due to incomplete data, 8 patients were excluded from the analysis. There was no correlation between result in lactose tolerance test (blood glucose analysis) and any of the registered symptoms or lactose transit time. Discussion and Conclusions: Results of the two used lactose absorption tests were unexpectantly dissimilar. In adult patients the breath hydrogen analysis is not suitable for diagnostics of lactose malabsorption.