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Definition
The fecal immunochemical test finds hidden (occult) blood in the stool (bowel movement). It is significantly more effective at detecting traces of blood than the traditional guaiac smear test.
How the test is performed
A kit will be provided to you prior to your hospital visit. Stool samples from two bowel movements are collected, smeared on a card, and brought to the hospital for processing. In order to ensure the accuracy of the test, follow the manufacturer's instructions on how to collect the stool.
The test kit supplies a special toilet tissue that you use to collect the sample, then put the sample in a clean container. Do not take stool samples from the toilet bowl water, because this can cause errors.
For infants and young children wearing diapers, you can line the diaper with plastic wrap. The plastic wrap is positioned so that it keeps the stool from any urine. Mixing of urine and stool can spoil a good sample.
How to prepare for the test
Do not eat red meat, any blood-containing food, cantaloupe, uncooked broccoli, turnip, radish, or horseradish for 3 days prior to the test.
You may need to stop taking medicines that can interfere with the test. These include vitamin C and aspirin. Check with your health care provider regarding medication changes that may be necessary. Never stop or decrease any medication without consulting your health care provider.
How the test will feel
There is no discomfort when the test is done at home, because this test only involves normal bowel functions.
Why the test is performed
This test is a screening test to detect blood in the digestive tract.
Normal Values
A negative test result is normal.
What abnormal results mean
Abnormal results may indicate:
- Colon polyps
- Colon cancer or other gastrointestinal (GI) tumors
- Esophagitis
- Gastritis
- GI trauma or bleeding from recent GI surgery
- Hemorrhoids
- Inflammatory bowel disease
- Peptic ulcer
- Angiodysplasia of the GI tract
- GI infections
- Esophageal varices and portal hypertensive gastropathy
Additional non-GI related causes of abnormal results may include:
- Nose bleed
- Coughing up blood
Abnormal tests require follow-up with your doctor.
What the risks are
There can be false-positive and false-negative results. Using the right collection technique, avoiding certain drugs, and observing food restrictions can reduce errors. |
