Test Overview
Guaiac procedure for detection of occult blood.
This test is a qualitative method for detecting fecal occult blood which may be indicative of gastrointestinal disease. It is not a test for colorectal cancer or any other specific disease. Serial fecal specimen analysis is recommended when screening asymptomatic patients.
Negative
* Reference ranges may change over time. Please refer to the original patient report when evaluating results.
Intake of foods such as red meat, broccoli, turnips, cauliflower, apples, oranges, mushrooms, and horseradish, and drugs such as colchicine and oxidizing drugs (like iodine and boric acid) may give a false positive result. Intake of vitamin C in excess of 250 mg/day may give a false negative result.
Test Details
8 hours
- Guiac Test
- Hemoccult, Stool
- Occult Blood, Stool Card
Specimen Requirements
Collect feces from the sample collection paper or specimen caught in a clean cup or collected during physical exam (i.e. DRE). Contamination from toilet water should be avoided. Using an applicator stick, collect a small fecal sample. Apply thin smear to Box A. Reuse applicator to obtain a sample from a different part of feces. Apply thin smear covering Box B. Close cover flap and dispose applicator in waste container. Send the sample card(s) to the laboratory.
Additional Information
Please see Fecal Occult Blood, Immunoassay (IFOB) for qualitative detection of fecal occult blood in feces recommended for use in routine physical exams, monitor for bleeding in patients and screening for colorectal cancer or other GI disorders that can cause gastrointestinal bleeding (e.g., diverticulitis, polyps, and Crohn's disease).