There are several different types of breath test that can be used as noninvasive ways to study a variety of gastrointestinal and inherited metabolic conditions. Sometimes a patient factor may affect the accuracy of the test.
Patient factors that may affect the accuracy of a breath test:
(1) difficulty collecting an entire specimen (infant, dementia, etc)
(2) deviations from the collection schedule
(3) altered basal metabolic rate, including children who will not stay still, fever, etc
(4) increased carbon dioxide generation for other reason
(5) uremia (in the case of the urea test)
(6) previous gastric surgery
(7) altered gastrointestinal motility
(8) medications
(9) achlorhydria
(10) diffuse inflammation in the gastrointestinal tract
Sometimes testing on blood samples can provide relevant information, but then the breath test is no longer noninvasive.
