Protein - urine

Definition

A urine albumin test measures the amount of protein in urine.

Alternative Names

How the test is performed

Urine protein is tested by one of these methods:

1. To quickly see whether or not protein is present in urine, a "spot test" is used. In this test, a chemically treated stick is dipped into a random sample of urine, simply to see if protein is detectable.
2. To actually measure how much protein is being excreted in the urine, a 24-hour urine sample is required.

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 when you get up in the morning.
• Afterwards, collect all urine in a special container for the next 24 hours.
• On day 2, urinate into the container when you get up in the morning.
• 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.

In infants, 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 the infant. For boys, the entire penis can be placed in the bag and the adhesive attached to the skin. For girls, the bag is placed over the labia. Diaper as usual over the secured bag.

This procedure may take a couple of attempts -- lively infants can displace the bag. The infant should be checked frequently and the bag changed after the infant has urinated into the bag. 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.

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 found in urine when a routine dipstick test is performed. This is because the kidney is supposed to keep large molecules, such as protein, in the blood and only filter out smaller impurities. Even if small amounts of protein do get through, they are normally re-absorbed by the body and used as a source of energy.

Some proteins will appear in the urine if the levels of protein in blood become high, even when the kidney is functioning properly.

If the kidney is diseased, protein will appear in the urine -- even if the blood levels are normal.

Normal Values

• For a spot check by dipstick: the normal values are approximately 0 to 8 mg/dl. Normal value ranges may vary slightly among different laboratories.
• For a 24-hour test: the normal value is less than 150 mg per 24 hours.

Note: mg/dl = milligrams per deciliter

What abnormal results mean

Abnormal results may mean an increase in urine protein, and this may indicate:

• Amyloidosis
• Bacterial pyelonephritis
• Bladder tumor
• Congestive heart failure (inadequately perfusing the kidneys)
• Diabetic nephropathy
• Glomerulonephritis
• Goodpasture's syndrome
• Heavy metal poisoning
• Lupus erythematosus
• Malignant hypertension
• Multiple myeloma
• Nephrotic syndrome
• Nephrotoxic drug therapy
• Polycystic kidney disease
• Preeclampsia

• Acute nephritic syndrome
• Complicated UTI (pyelonephritis)
• Eclampsia
• Hemolytic-uremic syndrome (HUS)
• Interstitial nephritis
• Medullary cystic disease
• Membranoproliferative GN I
• Membranoproliferative GN II
• Membranous nephropathy
• Necrotizing vasculitis
• Post-streptococcal GN
• Rapidly progressive (crescentic) glomerulonephritis
• Reflux nephropathy
• Renal vein thrombosis
• Rocky mountain spotted fever

What the risks are

There are no risks.

Special considerations

Interfering factors include:

• Severe emotional stress
• Strenuous exercise
• Radiopaque contrast media within 3 days of the urine test
• Urine contaminated with vaginal secretions