American Board of Pathology (ABPath) Practice Test 2026 - Free Pathology Exam Practice Questions and Study Guide

The necessity for a patient to be NPO (nil per os, or nothing by mouth) prior to a renal artery stenosis study typically relates to imaging techniques like a renal Doppler ultrasound or an angiogram. For many types of imaging studies involving contrast media or certain protocols, a fasting period helps ensure clear visualization of the renal arteries and reduces the risk of complications associated with the consumption of food or liquids, such as gastrointestinal interference or nausea during the procedure.

While the specific duration of NPO might vary based on the facility or the type of procedure, a commonly accepted standard is a fasting period of approximately 8 to 12 hours prior to the study. In this case, stating that the patient must be NPO for 12 hours aligns with conventional practice guidelines, especially for certain imaging tests.

The other options either suggest incorrect durations that do not align with typical protocols or state that fasting is not required at all, which would undermine the effectiveness of the study. Thus, the assertion that a patient must be NPO for 12 hours is consistent with clinical practice for ensuring optimal conditions for evaluating renal artery stenosis.