Serum Urea Nitrogen and Serum Creatinine Determinations Are Frequently Requested

Multiple Choice

Serum urea nitrogen and serum creatinine determinations are frequently requested together so that their ratio may be evaluated. What is the range of the normal ratio of urea nitrogen to creatinine?

A) 1/1 and 10/1
B) 12/1 and 20/1
C) 15/1 and 20/1
D) 20/1 and 30/1
E) 25/1 and 30/1