Protein - Urine
Alternate Names : Albumin - Urine, Albuminuria, Proteinuria, Urine Albumin, Urine Protein
Definition A urine albumin is a test that measures the amount of protein in urine.
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Why is the Test Performed?
This test is most often performed when kidney disease is suspected. It may be used as a screening test.
Normally, protein is not present in the urine when measured by routine dipstick qualitative tests. This is because the glomerulus (which is the part of the kidney nephron which filters fluid from the blood) generally prevents large molecules (which includes most proteins) from entering the renal filtrate.
Even if small amounts get through, they are normally taken up by renal tubular cells which then metabolize the proteins as a source of energy. However, even if both the glomerulus and renal tubules are completely normal, some proteins will appear in the urine if plasma (blood) concentrations exceed the threshold value. If the kidney is diseased, protein will appear in the urine -- even if the plasma concentrations are normal.
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