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

OBJECTIVES The hydrogen (H2) 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 H2 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 H2-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 H2 excretion was 9 ppm (range, 7-17) and delta increase over basal H2 excretion was 4 ppm (range, 1-6). Correlation between H2-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 H2 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.