What it means
"Occult" means hidden. The test looks for blood in the stool that the eye cannot see, which can come from anywhere in the digestive tract. It is used to screen for colorectal cancer and to look for slow GI bleeding. The older guaiac test (gFOBT) uses a chemical that changes color; the fecal immunochemical test (FIT) uses antibodies to human blood. A positive result is followed by a colonoscopy.
For the nurse
For the guaiac test, teach the client to avoid red meat, NSAIDs and large doses of vitamin C for a few days before, as directed, because they can change the result. Collect from three separate stools if ordered, without water or urine in the sample.
At a glance
| Normal range | Negative (no blood detected). |
|---|---|
| Abbreviations | FOBT; gFOBT (guaiac); FIT (fecal immunochemical test) |
| Spanish | prueba de sangre oculta en heces |
| Also written | FOBT, Hemoccult, guaiac test, stool guaiac |