Evaluation of Test Results

Diagnostic Criteria

Breath ¹³CO₂ is measured by isotope ratio mass spectrometry (IRMS) at baseline and at 30, 60 and 90 minutes post-ingestion of 20 grams of sucrose. Metabolic Solutions analyzes the tubes for the presence of ¹³CO₂ in the exhaled breath.  If the cumulative percent of the dose of sucrose metabolized at 90 minute is <5.10% for females or <3.91% for males, the test is considered positive for intestinal damage.

Causes of Unevaluable Tests

It is critical to the evaluation of the test that the breath be properly collected.  If the amount of CO₂ present in the tube is <2.0%, the ¹³C content cannot be reliably measured and the test will be unevaluable.

Causes of False-Negative or False-Positive Results

False-positive and false negative results are almost always the result of improper test preparation. Patients need to fast a minimum of 4 hours with a maximum of a 12 hour fast. Sleeping during the test can delay gastric emptying and slow down the metabolism of the sucrose.