13C maize starch breath test for pancreas function diagnosis
Properties of Pancreoamyl
Starch, an ubiquitous ingredient in food.
The labeled substrate is the largest cost factor of most 13C breath tests. In the case of pancreoamyl the price component is negligible.
The cornstarch substrate can be prepared tasty, the test is extremely easy to perform and no special equipment is needed on site.
Indications for the use of Pancreoamyl
Exocrine pancreatic insufficiency is associated with the decrease of various enzymes in pancreatic juice. Lipase (important in fat breakdown) and amylase (hydrolyzes starch) are important components of pancreatic secretion into the small intestine. The Pancreoamyl is a 13C maize starch breath test to detect amylase in vivo and thus measure pancreatic function. Conventional methods require urine or stool samples, so an effective breath test, especially when based on a naturally occurring substance such as cornstarch, is an attractive alternative.
Another advantage of an amylase breath test is the short time in which results are obtained. If a mass spectrometer is available, results can be obtained within four hours.
Principle and protocol for the Pancreoamyl test
Pancreoamyl differs from most breath tests in that the substrate is a naturally occurring substance. Starch derived from corn contains more 13C than starch from other sources such as rice or potatoes. This difference, which is related to the different type of photosynthesis, is quite small, but is sufficient to use corn starch as a naturally labelled substrate. This is at least the case in moderate climates, where carbon in food has a lower 13C content than maize.
The test principle of Pancreoamyl is based, like most breath tests, on the fact that in carbon substrates that are broken down in the intestine or other organs, any resulting 13CO2 enters the blood and appears in the breath very soon. Once the rate of conversion of 13C maize starch to 13CO2 in healthy individuals has been determined, the reduced production of 13CO2 in the breath can be attributed to exocrine pancreatic insufficiency.
The test is non-invasive, safe and can be repeated as often as required. INFAI has shown that the test detects pancreatic insufficiency with high sensitivity (88%) and specificity (82%).
After nightly fasting, two basal value breath samples are taken by breathing with a straw in 10 ml test tubes. The tubes are sealed with rubber stoppers and stored for further analysis.
The substrate (50 g free cornstarch in 100 ml water) is taken and further breath samples are taken and stored at half-hourly intervals within five hours.
A mathematical analysis of the 13CO2 excretion curve from the naturally labelled maize starch allows the identification of a patient with reduced amylase activity, which in turn signals exocrine pancreatic insufficiency.
- ¹³C-starch breath test comparative Clinical evalutation of an indirect pancreatic function test
Löser C., Möllgaard A., Aygen S., Hennemann O., Fölsch U. R.; Z. Gastroenterol. 33 (1997) 187-194