A creatinine clearance below 60 mL/min indicates what regarding nephron capacity?

A creatinine clearance test is used to assess how well the kidneys are filtering waste from the blood. Normal creatinine clearance rates typically range from about 90 to 120 mL/min, depending on various factors including age, muscle mass, and gender. A clearance rate below 60 mL/min signifies a significant decline in kidney function.

Specifically, a creatinine clearance rate under 60 mL/min typically indicates that there has been a loss of functional nephron capacity, which can be approximated to about 50% or more. The kidneys are composed of millions of nephrons, and when the creatinine clearance drops significantly, it usually reflects a substantial reduction in the number of nephrons that are effectively filtering blood.

This measure is clinically significant because it often serves as a marker for chronic kidney disease and may necessitate further evaluation or intervention. In terms of the provided answer options, the scenario aligns best with the understanding that a clearance below 60 mL/min correlates with a loss of about 50% of nephron function, rather than indicating complete renal failure, normal function, or dehydration.