Fecal Occult Blood Test (FOBT)

The Fecal Occult Blood Test (FOBT) is a non-invasive screening test used to detect hidden (occult) blood in the stool, which can be an early sign of colorectal cancer or other gastrointestinal disorders.

Purpose

The primary purpose of FOBT is to identify individuals who may have bleeding in the digestive tract, particularly in the colon or rectum, and require further evaluation and potential treatment.

Types of FOBT

There are two main types of FOBT:

• Guaiac-based FOBT (gFOBT): This type of test uses a chemical called guaiac to detect the presence of blood in the stool. It is the most commonly used method.
• Immunochemical FOBT (iFOBT): This type of test uses antibodies to detect specific proteins in the blood, providing more accurate results than gFOBT.

How the Test is Performed

To perform a FOBT, an individual collects a stool sample using a special card or device provided by their healthcare provider. The sample is then sent to a laboratory for analysis.

Interpretation of Results

The results of a FOBT can be either:

• Positive: Blood is detected in the stool, indicating potential bleeding in the digestive tract. Further testing, such as colonoscopy or sigmoidoscopy, may be necessary to determine the cause.
• Negative: No blood is detected in the stool, suggesting that there is no significant bleeding in the digestive tract.

Advantages and Limitations

FOBT has several advantages, including:

• Non-invasive and relatively inexpensive
• Easy to perform and interpret
• Can detect bleeding in the digestive tract early, potentially reducing the risk of colorectal cancer

However, FOBT also has some limitations:

• May produce false-positive or false-negative results
• Does not detect all types of gastrointestinal disorders
• Requires proper collection and handling of stool samples to ensure accurate results

Recommendations for Screening

The American Cancer Society recommends that adults aged 50-75 years undergo regular screening for colorectal cancer using FOBT, colonoscopy, or other methods. Individuals with a family history of colorectal cancer or other risk factors may need to start screening earlier.