A nurse is reinforcing teaching with a client who will collect stool specimens at home for fecal occult blood testing. Which of the following foods should the nurse instruct the client to avoid for 3 days before the test?

A. Red meat: Red meat contains heme, which can produce false-positive results on fecal occult blood tests by reacting with the guaiac reagent. Clients are advised to avoid beef, lamb, and liver for at least 3 days prior to testing to ensure accurate detection of gastrointestinal bleeding. B. Milk: Dairy products do not contain heme or other substances that interfere with the chemical reaction in guaiac-based fecal occult blood testing. Consumption of milk is generally safe and does not affect test accuracy. C. Almonds: Nuts are plant-based and do not contain heme. They may contribute to stool bulk but do not produce false-positive results in fecal occult blood tests. Avoidance is unnecessary. D. Whole wheat bread: Whole grains do not contain animal-derived heme and do not interfere with fecal occult blood detection. They are safe to consume prior to testing and do not affect test specificity.