The fecal occult blood test
(FOBT)

Sample type

Stool sample (feces)

Uses

The fecal occult blood test (FOBT) is a lab test used to check stool samples for hidden (occult) blood.

Occult blood in the stool may indicate colon cancer or polyps in the colon or rectum — though not all cancers or polyps bleed.

A test for fecal occult blood looks for blood in your poop, or feces. It can be a sign of a problem in your digestive system, such as a growth, or polyp, or cancer in the colon or rectum.

Precautions

No raw fruits.

No raw vegetables.

No red meat; you can eat chicken and pork.

Less than 250 mg per day of vitamin C-enriched foods or beverages in the 72 hours leading up to the test.

Interfering factors

Various foods, dietary supplements and medications can affect the results of some fecal occult blood tests — either indicating that blood is present when it isn’t (false-positive) or missing the presence of blood that’s actually there (false-negative). Your doctor may ask you to avoid certain foods or medicines.

Pre analytical errors

1- Incorrect Analysis ordered

2- patents identification error

3- sample collection errors

Corrective action

1- Using appropriate technology.

2- Monitoring quality indicators in the lab.

3- Choosing appropriate products.

Post analytical errors

1- Report delayed

2- incorrect interpretation

3- Sharing the results of patients or writing the result incorrectly.

Corrective action

1- Done Accurate Reports after doing tests

2- Assure that the prescribed preventive maintenance for the instruments is performed

3- Attention when delivered the results of patient and write them in the reports

Reference range

Tests for fecal occult blood detect blood in the stool that is not visible on gross inspection, usually less than 50 mg of hemoglobin per gram of stool. Normal adults usually show less than 2 to 3 mg/gm.