Which of the following falls within the normal range for BUN:Cr?

The normal range for the blood urea nitrogen (BUN) to creatinine (Cr) ratio typically falls between 10:1 to 20:1. A value of 15 mg/dL for BUN is within this normal range and indicates a healthy balance between these two measurements. This ratio is used to assess kidney function and hydration status; when both BUN and creatinine levels are normal, it usually signifies that the kidneys are functioning adequately.

Higher values such as 40 mg/dL, 55 mg/dL, and 100 mg/dL suggest potential issues. Elevated BUN levels can indicate dehydration, increased protein intake, or kidney dysfunction, while significant increases in creatinine levels generally point to impaired kidney function. Thus, the only option that suggests normal kidney function and hydration is a BUN level of 15 mg/dL.