Stool test

Stool iodine and saline wet mount

Guaiac test

US Air Force (USAF) Meredith Welsh, a Medical Technologist with the 39th Medical Group (MG), sets up a stool sample for testing at a Incirlik Air Base (AB), Turkey, laboratory - DPLA

Stool test, often referred to as fecal occult blood test (FOBT), is a diagnostic examination designed to detect hidden (occult) blood in the stool. Detecting hidden blood might indicate conditions such as colorectal cancer, ulcers, polyps, or other gastrointestinal abnormalities. In addition to detecting blood, stool tests can also be used to diagnose infections, digestive disorders, and other conditions based on the presence of specific substances in the stool.

Purpose

A stool test is mainly utilized to:

• Identify the presence of hidden blood which may be an early sign of conditions like colorectal cancer.
• Diagnose gastrointestinal infections caused by parasites, bacteria, or viruses.
• Evaluate digestive functions and conditions such as malabsorption.

Procedure

For a stool test, patients are usually provided with a kit to collect a sample at home. Instructions include:

• Avoiding certain foods or medications that might interfere with test results.
• Using an applicator or brush to place a small sample of stool onto a designated card or into a container.
• Returning the sample to the lab or healthcare provider for analysis.

Types

• Fecal occult blood test (FOBT): Focuses on the detection of hidden blood.
• Stool culture: Identifies harmful microorganisms that might be causing an infection.
• Stool antigen test: Determines the presence of specific substances that might indicate a disease or condition.
• Ova and parasites (O&P) examination: Detects parasites and their eggs in the stool.

Limitations

Stool tests, particularly FOBTs, can have false-positive or false-negative results. Factors that may cause false readings include certain foods, medications, and conditions unrelated to colorectal cancer.

Implications

Early detection of hidden blood in the stool can be crucial for diagnosing potential issues at a treatable stage, especially colorectal cancer. If blood is detected, further diagnostic procedures like a colonoscopy might be recommended.

See Also

• Colonoscopy
• Gastroenterology
• Digestive System

Stool test Resources
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