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Protein - urine
Definition
A protein urine test measures the amount of proteins, such as albumin, found in a urine sample.
A blood test may also be done to measure the level of protein or albumin. See also: Serum albumin
Alternative Names
Urine protein; Albumin - urine; Urine albumin; Proteinuria; Albuminuria
How the Test is Performed
Urine protein may be tested using a random sample of urine and a dipstick test, or it may require a 24-hour urine sample. See: 24-hour urine protein
How to Prepare for the Test
Different drugs can change the result of this test. Make sure your health care provider knows what medications you are taking.
The following may also interfere with test results:
- Dehydration
- Dye (contrast media) if you have a radiology scan within 3 days before the urine test
- Severe emotional stress
- Strenuous exercise
- Urinary tract infection
- Urine contaminated with fluids from the vagina
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. However, tiny amounts of protein can be detected using special methods. This is because the kidney is supposed to keep large substances like protein in the blood. Even if small amounts of protein do get through, the body normally reabsorbs them.
Some proteins will appear in the urine if the levels of protein in blood become high, even when the kidney is working properly.
If the kidney is diseased, protein will appear in the urine even if blood protein levels are normal.
Normal Results
For a random urine sample, the normal values are approximately 0 to 8 mg/dL.
For a 24-hour urine collection, the normal value is less than 80 mg per 24 hours.
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
Small increases in urine protein levels are usually not a cause for concern.
However, larger amounts of protein in the urine may be due to:
- Amyloidosis
- Bladder tumor
- Congestive heart failure
- Dehydration
- Diabetic nephropathy
- Glomerulonephritis
- Goodpasture syndrome
- Heavy metal poisoning
- Kidney-damaging drugs (nephrotoxic drugs)
- Polycystic kidney disease
- Preeclampsia
- Systemic lupus erythematosus
- Urinary tract infection
Other conditions under which the test may be performed:
- Acute nephritic syndrome
- Body-wide (systemic) infection (sepsis)
- Eclampsia
- Hemolytic-uremic syndrome (HUS)
- Interstitial nephritis
- Medullary cystic kidney disease
- Membranoproliferative GN I and GN II
- Membranous nephropathy
- Necrotizing vasculitis
- Post-streptococcal glomerulonephritis
- Rapidly progressive (crescentic) glomerulonephritis
- Reflux nephropathy
- Renal vein thrombosis
Risks
There are no risks.
References
Landry DW, Bazari H. Approach to the patient with renal disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 116.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
