Blood Test for Kidney Disease

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• Who has a blood test of kidney function?

A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a needle, or via fingerprick. It can be used to make a diagnosis of many diseases.
Blood test of kidney function measures how well your kidneys are functioning by checking the level of urea, creatinine and certain dissolved salts.
Urea is a byproduct of protein and it is normally filtered by kidneys. If high levels of urea build up in blood, it indicates that the kidneys may not be functioning properly, or that you are dehydrated.
Creatinine is a waste product from the metabolism of muscle. It passes into the bloodstream, and is usually eliminated from body in the form of urine. If creatinine level rises to higher than normal, it implies that the kidneys have been impaired significantly. Creatinine is usually a more accurate marker of kidney function than urea.
GFR measures how much blood is filtered by glomeruli each minute. GFR is a more accurate measurement of renal function than creatinine level. Blood creatinine can be used to estimate the GFR using age, sex, and race. The normal level of GFR is 90-125ml/min. GFR will decline as the kidney damage becomes more serious.
Electrolytes measure the levels of sodium, potassium, chloride and bicarbonate in blood. Abnormal blood levels of any of these may be due to a kidney problem.

Who has a blood test of kidney function?

*If you are suspected to have kidney disease, elevated levels of urea and creatinine indicate reduced renal function.
* It can be used as a general health assessment.
* If you are suspected to have dehydration.