Reference Range

Negative.

This is a quantitative assay but results are reported qualitatively as negative or positive for the presence of fecal occult blood. The cutoff for positivity is 100 ng/mL hemoglobin. 

Interpretation:

Positive: 

Further testing is recommended to determine the source of bleeding. This test is designed for preliminary screening and is not intended to replace other diagnostic procedures such as colonoscopy.

Negative: 

This test is designed for preliminary screening and is not intended to replace other diagnostic procedures such as colonoscopy. A negative result does not assure the absence of gastrointestinal bleeding. Some bowel lesions may not bleed or may bleed intermittently, or blood may not be univormly distributed in the fecal sample. This test will not detect upper gastrointestinal bleeding. 

Cautions/Limitations:

• This test will not detect upper gastrointestinal bleeding. Results should not be considered conclusive evidence of the presence or absence of GI bleeding or pathology. It is not intended for use in patients with upper GI bleeds. 
• A negative result does not assure absence of lesion due to intermittent bleeding of GI lesions and in some cases the total lack of bleeding. 
• A positive result should be followed up with further studies to establish source of bleeding. 
• Patients with the following conditions should not be considered for testing: Bleeding hemorrhoids, constipation bleeding, menstrual bleeding, and urinary bleeding.  Testing may occur when bleeding has ceased. 
• False positives may occur in some patients taking certain medications such as aspirin and non-steroidal anti-inflammatory drugs that cause gastrointestinal irritation and subsequent bleeding. 
• Urine of excessive dilution of the samples with water from the toilet bowel may cause false negatives. Use of the collection paper in the collection kit is recommended. 
• Test has not been validated for testing of patients with hemoglobinapthies.