Final answer:
To provide a rough estimate of kidney function, substances like blood urea nitrogen (BUN) and plasma creatinine are measured. These give an indication of how well the kidneys are filtering waste from the blood. Tests such as creatinine clearance and renal plasma flow further help in assessing kidney health.
Step-by-step explanation:
The estimation of kidney function can be rough guessed by measuring substances such as blood urea nitrogen (BUN) and plasma creatinine in the blood. Elevated levels of these substances may indicate reduced kidney function. BUN provides an estimate of the amount of urea in the blood, which is a waste product formed from the breakdown of proteins. The normal range for BUN is 8-20 mg/dl. Plasma creatinine, a waste product from muscle metabolism that is not reabsorbed significantly by the kidneys, also serves as a key indicator of kidney health, with normal values being 0.8-1.2 mg/dl for males and 0.6-0.9 mg/dl for females.
In addition to BUN and creatinine measurements, kidney function can also be evaluated by calculating the glomerular filtration rate (GFR), which is the best overall indicator of kidney function. GFR estimates the rate at which blood is filtered by the kidneys and can be closely estimated by the clearance of substances such as inulin or creatinine. A common clinical test for this purpose is the creatinine clearance test, which involves measuring the levels of creatinine in both blood and urine over a given time period to assess how well the kidneys are filtering it.
Other methods to estimate renal function include the concentration test and the renal plasma flow, which use substances like para-aminohippuric acid (PAH) to assess how well the kidneys are processing blood.