About BUN/Creatinine Ratio
The BUN-to-creatinine ratio is a quick tool for distinguishing different causes of elevated kidney markers. A high ratio (above 20) with elevated BUN suggests dehydration, high protein intake, or upper gastrointestinal bleeding — a 'pre-renal' cause where kidney function itself may be intact. A ratio below 10 with elevated creatinine points toward intrinsic kidney disease or low protein intake. The ratio is normal (10–20) in most people with stable, mild chronic kidney disease.