Ambulatory Care Nurse Certification Practice Exam 2026 - Free Practice Questions and Study Guide for Successful Certification

The blood urea nitrogen (BUN) to creatinine (Cr) ratio is an important indicator used in evaluating kidney function. Typically, a normal BUN level ranges from about 6 to 20 mg/dL, while normal creatinine levels vary by age, sex, and muscle mass, but generally fall between 0.6 and 1.2 mg/dL for adults.

The correct choice of 15 mg/dL falls within the normal range for BUN, which indicates that the kidney is functioning properly and metabolizing waste correctly. In assessing the BUN:Cr ratio, a normal value typically indicates no severe kidney dysfunction or dehydration, making this a key measurement for healthcare providers.

Values such as 40 mg/dL, 55 mg/dL, and 100 mg/dL are elevated and could signal potential issues such as dehydration, increased protein breakdown, or impaired kidney function, leading to a deceptive ratio that may complicate the evaluation of a patient’s kidney health. Therefore, the recognized normal value of BUN at 15 mg/dL is important in developing an appropriate clinical assessment and management plan.