Test for hidden blood in feces: an explanation
A positive fecal occult blood test (FOBT) could be a sign of a potential gastrointestinal issue, and it's crucial to understand what it means. FOBTs are noninvasive lab tests that check stool samples for the presence of blood, which could be a symptom of various conditions.
There are several common conditions that can cause gastrointestinal bleeding, as indicated by a positive FOBT. These include colorectal cancer and polyps, diverticular disease, inflammatory bowel diseases (IBD), hemorrhoids, esophageal causes, vascular abnormalities, infectious causes, ischemic colitis, and gastrointestinal ulcers.
For a FOBT, a person should collect the sample by flushing the toilet 2-3 times before collecting, scraping the stool's surface with a brush, and rubbing the brush on the indicated space on the testing card. The guaiac fecal occult blood test (gFOBT) uses a chemical called alpha guaiaconic acid or guaiac to detect blood in the stool, while the fecal immunochemical test (FIT) uses antibodies that bind to hemoglobin in the stool sample. In some cases, multiple stool samples from 2-3 separate bowel movements may be required.
The FIT-DNA test, a more advanced type of FOBT, uses a combination of antibodies used in the FIT test and altered DNA material associated with colorectal cancer. For this test, a person collects a stool sample in a tube and sends it to a lab for analysis.
Health experts often use FOBTs for cancer screening before a person shows any symptoms. They can also help find the cause of anemia and help determine if a person has IBD rather than irritable bowel syndrome (IBS).
A positive FOBT result often prompts further diagnostic evaluation, such as a colonoscopy, to identify the exact cause and appropriate treatment. A negative test result means that the test did not detect blood in the sample, and a doctor may suggest repeating the test in a year. However, false negatives can occur in people taking more than 250 milligrams of vitamin C daily.
It's essential to note that a positive FOBT result indicates that the individual has blood in their stool, but it is not a diagnosis of cancer. A doctor will typically recommend additional tests to help reach a diagnosis.
To prevent false-positive results, a person should discuss their menstrual period, hematuria, or bleeding hemorrhoids with their healthcare professional. Certain medications and foods may also affect the results of the test and should be avoided before testing. Examples include aspirin, heparin, warfarin, clopidogrel, nonsteroidal anti-inflammatory drugs (NSAIDs), selective serotonin reuptake inhibitors (SSRIs), antacids, iron supplements, red or rare meat, raw fruits, raw horseradish, raw turnips, cantaloupe, broccoli, cauliflower, parsnips, and red radishes.
Occult blood refers to microscopic blood that the naked eye cannot detect. FOBTs are an essential tool in colorectal cancer screening, and regular testing can help catch potential issues early. If you have any concerns or questions about FOBTs or colorectal cancer screening, please consult your healthcare professional.
- Colorectal cancer, a serious medical condition, is one of several common causes of gastrointestinal bleeding indicated by a positive fecal occult blood test (FOBT).
- For a thorough evaluation and potential treatment, a positive FOBT result often prompts further diagnostic measures like a colonoscopy, a medical procedure used to examine the colon's lining.
- Steps in promoting health and wellness can include understanding various medical conditions such as colorectal cancer, and adopting preventive measures such as regular FOBTs, an essential tool in colorectal cancer screening.
