13C-mixed triglyceride breath test for evaluation of pancreatic exocrine function in diabetes mellitus.

OBJECTIVE: The clinical relevance of pancreatic exocrine insufficiency (PEI) in diabetic patients is unclear mostly because established function tests are invasive and expensive or lack sensitivity and specificity. A modified version of the noninvasive 13C-mixed triglyceride breath test (13C-MTGT) has recently been shown to detect moderate PEI reliably in patients with chronic pancreatitis. Its sensitivity and specificity in other patient groups are unknown. We therefore aimed to clarify the significance of this test for patients with diabetes mellitus (DM). METHODS: A secretin cerulein test and a modified 13C-MTGT were performed in 14 patients with DM (10 patients with type 1 DM) and 10 healthy volunteers. RESULTS: Secretin cerulein test showed significantly lower outputs of amylase, trypsin, and lipase in DM compared with healthy volunteers (P < 0.05). Likewise, 13C-MTGT showed significantly lower maximal and cumulative 13C-exhalation in DM (P < 0.005). Stimulated lipase output correlated with cumulative 13C-exhalation (P < 0.05). However, when compared with normal values, only 2 patients with diabetes had abnormally low lipase output, whereas cumulative 13C-exhalation was pathologically decreased in 8 patients, including those with decreased lipase output. CONCLUSIONS: The noninvasive 13C-MTGT can detect mild to moderate PEI in DM. However, the specificity of the 13C-MTGT is low in these patients probably because nonpancreatic mechanisms contribute to decreased intestinal lipolysis.

A modified ¹³C-mixed triglyceride breath test detects moderate pancreatic exocrine insufficiency.

OBJECTIVES: The noninvasive ¹³C-mixed triglyceride breath test (¹³C-MTG-T) has been shown to diagnose severe pancreatic exocrine insufficiency reliably. We hypothesized that sensitivity of the test could be increased by strict limitation of physical activity, correction for gastric emptying velocity, and/or increased lipid dose. METHODS: In 10 healthy volunteers and 9 patients with suspected pancreatic disease, a secretin test, a modified ¹³C-MTG-T (250 mg ¹³C-MTG, 26 g fat, breath samples over 8 hours), and a ¹³C-octanoic acid gastric emptying test were performed. Subjects remained strictly seated during breath testing. RESULTS: Intravenously administered secretin 1 U/kg·h stimulated outputs of all enzymes significantly. Mean basal and stimulated enzyme outputs were similar in patients and healthy controls; however, compared with normal values, 5 patients and 1 control had moderately decreased lipase output. Cumulative 4-, 6-, and 8-hour ¹³C exhalation was significantly lower in patients than in controls. Sensitivity of ¹³C-MTG-T (6-h cumulative ¹³C exhalation <27% of dose) for detection of decreased lipase output was 100%; specificity was 92%. Gastric emptying parameters were similar in patients and controls, and correction for these did not improve accuracy of ¹³C-MTG-T. CONCLUSIONS: The modified ¹³C-MTG-T detects moderate pancreatic exocrine insufficiency.