BLOOD UREA NITROGEN (BUN)

Overview

Blood urea nitrogen (BUN) can rise due to prerenal (e.g., dehydration, heart issues), renal (e.g., nephritis, polycystic kidney disease), or postrenal causes (e.g., urinary tract obstructions). While BUN levels provide insights into kidney function, they are less sensitive than BUN or creatinine clearance tests. Clinicians often use the BUN-to-creatinine ratio to better assess kidney health.