A patient expresses concerns over having black stool. The fecal occult blood test is negative. Which response by the nurse is most appropriate?

Choice A reason: A negative fecal occult blood test suggests no gastrointestinal bleeding, reducing the urgency for a colonoscopy. Black stool can result from benign causes like iron supplements, so immediate invasive procedures are not warranted without further history or symptoms. Choice B reason: Assuming a false negative without evidence is premature. Fecal occult blood tests are reliable for detecting bleeding. Black stool may stem from non-bleeding causes like medications or diet, and suggesting a false result could unnecessarily alarm the patient. Choice C reason: Stress does not directly cause black stool. While stress can exacerbate gastrointestinal issues, black stool is more likely due to dietary factors, medications, or rare conditions. This question is vague and less relevant to the symptom’s likely etiology. Choice D reason: Iron supplements commonly cause black stool due to the oxidation of iron in the gastrointestinal tract, a benign side effect. Given the negative fecal occult blood test, asking about iron supplements is the most appropriate, targeted response to identify a likely cause.