C-13-mixed-triglyceride CO2-exhalation test: Examination of indirect exocrine pancreatic function using an isotope-selective nondispersive infrared spectrometer.

Background and objective: The C-13-mixed-triglyceride CO2-exhalation test ( MTE) has been proposed for the noninvasive assessment of intraluminal duode nal pancreatic lipase activity. Up to now, stable isotope analysis of carbo n dioxide of the MTE has been carried out with isotope ratio mass-spectrome try. The aim of the present study was to evaluate the MTE in patients with morphological signs of chronic pancreatitis (stages I-III) and exocrine pan creatic insufficiency by using an isotope-selective nondispersive infrared spectrometer (NDIRS). Patients and methods: 20 healthy volunteers (9 females, 11 males, age range 19-61 years) and 16 patients (7 females, 9 males, age range 33-76 years) w ere examined. After an overnight fast each patient received a solid-liquid test meal containing 250 mg 1,3 distearyl, 2[C-13] octanoyl glycerol. Breat h samples were obtained at baseline and at 30 min intervals over a period o f 6 h after the test meal. The C-13/C-12 isotope ratio in each breath sampl e was determined by NDIRS as delta (%) and delta over baseline (%). Results were expressed as cumulative percentage dose of C-13 recovered (cPDR) at 3 , 4, 5, 6 h and maximal PDR (PDRpeak) (median; 5./95. percentile). Results: Significant lower values concerning cPDR 3, 4, 5, 6 hours and PDRp eak [%] were found between healthy subjects and patients with chronic pancr eatitis (p < 0.05): cPDR 6 h: 8.1 (0.4-20.5)% vs 29.1 (10.3-59.3)%; PDRpeak : 4.7 (0.4-10.2)% vs 9.2 (5.4-14.3)%. Interpretation: In general, the MTE discriminates between healthy controls and patients with chronic pancreatitis and exocrine pancreatic insufficienc y. However, the MTE using NDIRS cannot be recommended as a method of clinic al routine because of marked data overlap between pathologic and normal val ues.