CAMRT Radiography Practice Exam

What do Blood Urea Nitrogen (BUN) levels primarily assess?

1. Heart function

2. Kidney function

3. Liver function

4. Lung function

The correct answer is: Kidney function

Blood Urea Nitrogen (BUN) levels primarily assess kidney function. Urea is a waste product formed in the liver from the breakdown of proteins. It is then filtered out by the kidneys and excreted in urine. Evaluating BUN levels helps to determine how well the kidneys are functioning in removing waste from the bloodstream. Elevated BUN levels may indicate impaired kidney function, dehydration, or a high protein diet, while low levels could suggest liver disease or malnutrition. The context around the other options clarifies why they are less relevant. For instance, while heart function is assessed through different markers like creatinine kinase or troponin levels, and liver function is often evaluated using liver enzyme tests (such as ALT and AST), lung function assessments typically involve spirometry or imaging tests focused on respiratory health. Thus, BUN reflects specific aspects of kidney performance, making it the correct choice.