Before a gFOBT, which dietary precaution is recommended?

Before a gFOBT, which dietary precaution is recommended?

• A. Not drinking water
• B. Fasting for 12 hours
• C. Avoid Dairy Products
• D. Not eating meat 3 days prior

Answer: (D)

The test works by using guaiac as a substrate to detect peroxidase activity in stool, which can indicate hidden blood. Substances with peroxidase activity, especially heme from red meat, can trigger a color change even if there isn’t actual bleeding. To reduce false positives, patients are commonly advised to avoid red meat for several days before the test, typically about three days. This is why not eating meat three days prior is the appropriate precaution. The other options don’t affect the guaiac reaction in the same way: drinking water, fasting, or avoiding dairy products aren’t known to interfere with the test’s chemistry in a meaningful way.

The test works by using guaiac as a substrate to detect peroxidase activity in stool, which can indicate hidden blood. Substances with peroxidase activity, especially heme from red meat, can trigger a color change even if there isn’t actual bleeding. To reduce false positives, patients are commonly advised to avoid red meat for several days before the test, typically about three days. This is why not eating meat three days prior is the appropriate precaution.

The other options don’t affect the guaiac reaction in the same way: drinking water, fasting, or avoiding dairy products aren’t known to interfere with the test’s chemistry in a meaningful way.