BUN / Creatinine Ratio

What it isA simple ratio of BUN to creatinine that helps distinguish pre-renal causes of elevated BUN (dehydration, bleeding) from intrinsic kidney disease.

DoesActs as a diagnostic clue when BUN is elevated — same BUN, different ratio, different story.

GoodA mid-range ratio with both components in their optimal ranges indicates balanced hydration and intact kidney.

BadA high ratio with normal creatinine suggests dehydration or upper GI bleed; a low ratio suggests low protein intake or liver disease; a high ratio with elevated creatinine suggests prerenal kidney injury.