Hydrogen breath test with low-dose rice flour for assessment of exocrine pancreatic insufficiency

Objectives: The hydrogen (H-2) breath test is widely used in the assessment of carbohydrate malabsorption. Severe exocrine pancreatic insufficiency markedly diminishes pancreatic amylase production and results in malabsorption of complex carbohydrates. Thus, the H 2 breath test with low-dose rice flour starch was tested to determine its value in detecting exocrine pancreatic insufficiency by comparison with a direct measurement of pancreatic function. Methods: Ten patients with clinically suspected pancreatic insufficiency confirmed with a duodenal perfusion technique and measurement of trypsin and lipase output after cerulein stimulation were included. An H-2-rice flour breath test was performed by orally administering 30 g of rice flour. End-alveolar breath samples were obtained before rice load and at 30-minute intervals thereafter for the next 5 hours. Results: The results are expressed as median ( percentile 25 - 75). Patients included 8 men and 2 women with moderate to severe exocrine pancreatic insufficiency due to chronic pancreatitis, pancreatectomy, or cystic fibrosis. Stimulated duodenal output of lipase and trypsin was abnormally low in all patients ( median release, 1.7; range, 0.5 - 4.5 and 0.8, range, 0.1 - 11.3 KU/h, respectively). Basal H-2 excretion was 9 ppm ( range, 7 - 17) and delta increase over basal H-2 excretion was 4 ppm ( range, 1 - 6). Correlation between H-2-rice breath test and basal or stimulated duodenal output of lipase and trypsin was not significant. Conclusion: In exocrine pancreatic insufficiency, an oral load of 30 g rice flour slightly raises H-2 excretion in breath. This increase is not useful for detecting pancreatic insufficiency due to poor sensitivity and because it is influenced by extrapancreatic factors such as small bowel bacterial overgrowth.