Properties of Gastromotal®

  • Non radioactive
    Scintigraphy uses radioactive isotopes. ¹³C is a stable isotope and therefore inherently safer than a test with radioisotopes.
  • Inexpensive
    The ¹³C-octanoic acid breath test can be performed at a fraction of the cost of scintigraphy and is more accurate than ultrasound imaging.

Indications for the use of Gastromotal

Gastromotal is a 13C-octanoic acid breath test to measure the rate at which solid stomach contents enter the small intestine. Stomach motility is affected by a number of clinical conditions, including diabetes, non-ulcer dyspepsia, GERD and some post-operative conditions. Recent developments of drugs that affect gastric motility have led to renewed interest in this topic.

INFAI has completed clinical trials for this test and is currently applying for pan-European approval. The kit is currently available on a per-patient basis and for research projects, subject to appropriate ethical and licensing exclusions.

Test principle and protocol of Gastromotal


The techniques currently used to determine gastric emptying (scintigraphy and ultrasound) have significant shortcomings, so a new, better test will be of significant value. Ghoos et al (Gastroenterology, Vol 104, 1640-1647, 1993) described a 13C-octanoic acid breath test in which the substrate is presented with egg in a test meal and the emergence of 13CO2 in breath is monitored. 13C-octanoic acid is a normal component of foods such as butter, so no negative side effects are expected. The mathematical analysis of the excretion curve, using a method developed by INFAI, allows to determine the gastric emptying rate. The test allows non-invasive detection of patients with gastric motility problems and evaluation of motility enhancing drugs.

The patient consumes 13C-octanoic acid on an empty stomach. It is mixed with raw egg yolk, fried and served with bread, butter and 150 ml coffee or tea. In this form, the 13C-octanoic acid is only released upon arrival in the small intestine, where it is absorbed and quickly metabolized in the liver. The resulting 13CO2 appears almost immediately in the breath and is collected in glass sample tubes into which the patient breathes with a straw, which are sealed and stored until analysis. Two breath samples are taken directly before the test, ten samples at 15-minute intervals after the test meal, and another three at half-hourly intervals, covering a total measurement time of 240 minutes. The tubes are sent to a qualified laboratory for 13CO2 analysis and the excretion curve is mathematically analyzed to distinguish between normal and impaired gastric motility. Two parameters (gastric emptying coefficient and half time of gastric emptying) are calculated and reported using a mathematical procedure and software developed by INFAI.

Since the test measures exactly the time at which solid material appears in the small intestine, the preparation of the test meal is crucial for the accuracy of the test. If the test meal is prepared incorrectly, the liquid phase marker can be washed out of the stomach to mask reduced gastric motility.

Ongoing study on Gastromotal

Study: Gastromotal; Eudra CT Number: 2011-002782-38
Gastromotal 1-¹³C-Caprylic Acid breath test in the diagnosis and evaluation of therapeutic outcome in patients with dyspeptic symptoms and delayed emptying. Sponsor: INFAI

Gastromotal Patent

  • EP1553987, Method for determining gastric evacuation using a 13C-labelled test meal, European Patent, 01.08.2007
  • US20060057181, Method for determining gastric evacuation using a 13C-labelled test meal, US Patent, 16.03.2006
  • US20120071728, Method for determining gastric emptying, US Patent, 22.03.2012
  • WO2004037298, Method for determining gastric evacuation using a 13C-labelled test meal, International Patent, 06.05.2004


  • Ghoos YF, Maes BD, Geypens BJ, Mys G, Hiele MI, Rutgeerts PJ, Vantrappen G (1993): Measurement of gastric emptying rate of solids by means of a carbons-labeled octanoic acid breath test. Gastroenterology 104(6): 1640-7. PUBMED

  • Pfaffenbach B, Wegener M, Adamek RJ, Wissuwa H, Schaffstein J, Aygen S, Hennemann O (1995): Non-invasive ¹³C octanoic acid breath test for measuring stomach emptying of a solid test meal--correlation with scintigraphy in diabetic patients and reproducibility in healthy probands. Z. Gastroenterol. 33(3): 141-5. PUBMED
  • Choi, MG., Camilleri M., Burton DD., Zinsmeister AR., Forstrom LA., Nair KS. (1998): Reproducibility and simplification of ¹³C-octanoic acid breath test for gastric emptying of solids. Am. J. Gastroenterol. 93: 92-98. PUBMED

  • Maes BD., Spitz B., Ghoos YF., Hiele MI., Evenepoel P, Rutgeerts PJ. (1999): Gastric emptying in hyperemesis gravidarum and non-dyspeptic pregnancy. Aliment Pharmacol Ther 13: 237-243. DOI

  • H. Steinbrede, S. Aygen, G.Eibes, C. Steinborn: The effect of multiple doses of KC 11458, a new motilin agonist, on gastric emptying of a solid test meal in healthy male volunteers, Gastroenterology 114, No. 4, G3455 DOI:

  • RUSSO, J. E. STEVENS, N. GILES, G. KRAUSE, D. G. O’DONOVAN, M. HOROWITZ, K. L. JONES: Effect of the motilin agonist KC 11458 on gastric emptying in diabetic gastroparesis, Aliment Pharmacol Ther 2004; 20: 333–338. DOI