Triglyceride breath test

Figure 26-5. Principle of the 13C-mixed triglyceride breath test. Absorption of 13C-mixed triglycerides requires prior hydrolysis by pancreatic lipase (1), which leads to production of free fatty acids (stearic acid) and monoacylglycerol [2-(l-13C)octanoylglycerol]. These metabolites are incorporated into micelles, absorbed, and transported to the liver (2). Further degradation by hepatic enzymes and P-oxidation results in formation of 13C02, which is absorbed into the bloodstream, transported to the lung, and exhaled (3). Thus, exhalation of 13C02 reflects intestinal lipolysis and is a marker of pancreatic exocrine function.

Vantrappen GR, Rutgeerts PJ, et al. Mixed triglyceride breath test a noninvasive test of pancreatic lipase activity in the duodenum. Gastroenlerol-ogy 96 1126-1134,1989. 

AH of the other noninvasive tests are based on the reduction in the secretion of pancreatic enzymes with direct measurement of enzymes in feces (chymotrypsin or elastase) or detection of products of their catalytic reactions, after oral administration of synthetic substrates, in urine (NBT-PABA or pancreolauryl test) or in breath ( C-mixed chain triglyceride breath test). 

Figure 48-9 The substrate for the C-mixed chain triglyceride breath test 1,3 distearyl,2(carboxyi- C) octanoyl glycerol.

Liver, thyroid, and severe respiratory disease, diabetes, obesity, pregnancy Mixed-chain triglyceride breath test Valid test for pancreatic steatorrhea Fat globules (fecal microscopy)... 

Amarri S, Harding M, Coward WA, Evans TJ, Weaver LT. C-mixed triglyceride breath test and pancreatic enzyme supplementation in children with cystic fibrosis. Arch Dis Childhood 1997 76 349-51. 

Loser C, Brauer C, Aygen S, Hennemann O, Folsch UR. Comparative clinical evaluation of the C-mixed triglyceride breath test as an indirect test of pancreatic function. Scand J Gastroenterol 1998 33 327-34,... 

C-iriglycerule breath test. An oral dose of radiolabellcd triglyceride (e.g. C-lriolein in which the fatty acid contains the label) is absorbed and metabolized. The "CO, in expired air is a measure of the effectiveness of digestion and absorption. 

The C-mixed chain triglyceride test is designed as a test of intraluminal pancreatic lipase activity.The substrate for the test is 1,3-distearyl>2( carboxyl- C) octanoyl glycerol, which contains long chain fatty acids in positions 1 and 3 and the C-labeled medium chain fatty acid (octanoic acid) in position 2 (Figure 48-9). The labeled substrate is administered orally to fasting patients with a standard meal of toast and butter. Breath samples are collected over a 5-hour... 

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