BUN:Creatinine Ratio is Nothing Without the BUN

The ratio of BUN to creatinine provides information about protein metabolism and kidney function. Both markers are considered end products of nitrogen metabolism and levels in the blood depend on protein intake, protein breakdown, muscle mass, and kidney function.

Normally the BUN:Creatinine ratio remains close to 15. However, the ratio can increase above 20 with acute overload due to catabolic states, fever, burns, congestive heart failure, COVID-19, urinary trat obstruction, and other acute conditions that may resolve.

If the ratio decreases below 10, then kidney damage and persistent dysfunction is likely and the possibility of renal failure must be evaluated. A low level may also be associated with inadequate protein intake, increased creatinine production (e.g., rhabdomyolysis), decreased urea synthesis (e.g., liver dysfunction), inflammation, and oxidative damage.

Want to Learn More?

CLICK HERE to learn more about BUN:Creatinine ratio, optimal ranges, kidney function, optimal ranges, etc.