What does creatinine clearance (CrCl) measure?

Creatinine clearance (CrCl) is an important clinical test used to assess kidney function, specifically measuring the glomerular filtration rate (GFR). The GFR indicates how effectively the kidneys are filtering blood, a crucial function for maintaining overall health.

In this context, creatinine is a waste product produced from muscle metabolism, and its levels in the blood can suggest how well the kidneys are working. When creatinine is cleared from the blood and filtered through the glomeruli of the kidneys, it gives an indirect measure of the rate at which the kidneys can filter blood.

The calculation for creatinine clearance involves measuring the concentration of creatinine in both urine and blood over a specified period. A decrease in the creatinine clearance value typically indicates impaired kidney function, thus providing healthcare providers with essential information regarding the status of renal health.

Other options refer to different parameters that are not directly related to the specific measurement provided by creatinine clearance. For example, blood volume and plasma concentration pertain to overall fluid status and the concentration of substances in plasma, while residual urine relates to leftover urine in the bladder after voiding, none of which directly measures kidney filtration capacity like creatinine clearance does.