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Ency. home > Test > P > Protein - urine

Protein - urine    See images

Overview | Risks | Results

Alternative names:

Urine protein; Albumin - urine; Urine albumin; Proteinuria; Albuminuria

Definition:

A urine albumin is a test that measures the amount of protein in urine.

How the Test is Performed

Urine is collected by 1 of 2 methods.

Urine protein can be detected in a "spot test" by dipstick (a specially treated stick is dipped into a random sample of urine), or quantitated in a 24 hour sample.

The health care provider will instruct you, if necessary, to discontinue drugs that may interfere with the test. The procedure for collecting urine over 24 hours is as follows:

  • On day 1, urinate into the toilet upon arising in the morning.
  • Collect all subsequent urine (in a special container) for the next 24 hours.
  • On day 2, urinate into the container in the morning upon arising.
  • Cap the container. Keep it in the refrigerator or a cool place during the collection period. Label the container with your name, the date, the time of completion, and return it as instructed.

Infant:
Thoroughly wash the area around the urethra. Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on your infant. For males, the entire penis can be placed in the bag and the adhesive attached to the skin. For females, the bag is placed over the labia.

Place a diaper over the infant (bag and all). The infant should be checked frequently, and the bag changed after the infant has urinated into the bag. For active infants, this procedure may take a couple of attempts -- lively infants can displace the bag, causing an inability to obtain the specimen. The urine is drained into the container for transport to the laboratory.

Deliver it to the laboratory or your health care provider as soon as possible upon completion.

How to Prepare for the Test

The health care provider may advise the person to discontinue drugs that can interfere with the test (see Special Considerations).

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

How the Test will Feel

The test only involves normal urination, and there is no discomfort.

Why the Test is 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.

Ency. home > Test > P > Protein - urine

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