What Is a Protein Urine Test?
A protein urine test is used to measure the amount of protein in urine. Normally, healthy individuals do not have protein in their urine. However, when the kidneys are not working properly, protein may be excreted in the urine. Protein may also be found in the urine if there are high levels of certain proteins in the bloodstream.
A urine test for protein may be done as a random one-time sample or a 24-hour collection sample. A urine protein test is also called urine albumin test or proteinuria.
Why Is the Test Ordered?
Your doctor may order this test if he or she suspects a problem with your kidneys. Your doctor may order the test to see if the condition is responding to treatment if you currently have a kidney condition. This test may also be ordered if you have symptoms of a urinary tract infection (UTI) or as part of a routine urinalysis.
A small amount of protein in the urine is normally not a problem. However, larger levels of protein in the urine may be caused by:
- urinary tract infection
- kidney infection
- amyloidosis (a build-up of protein in the body’s tissues)
- drugs that damage the kidneys (such as NSAIDs, antimicrobials, diuretics, and chemotherapy drugs)
- hypertension (high blood pressure)
- preeclampsia (high blood pressure in pregnant women)
- heavy metal poisoning
- polycystic kidney disease
- congestive heart failure
- glomerulonephritis (a kidney disease that causes kidney damage)
- systemic lupus erythematosus (an autoimmune disease)
- Goodpasture syndrome (an autoimmune disease)
- multiple myeloma (a type of cancer affecting bone marrow)
- bladder tumor or cancer
Certain people are more at risk for developing kidney problems. Your doctor may order regular protein urine testing to help screen for kidney problems if you have one or more risk factors. Risk factors include:
- having a chronic condition such as diabetes or hypertension
- having a family history of kidney disease
- being of African American, American Indian, Hispanic American, or Pacific Islander descent
- being overweight
- being an older age
Preparing for Your Test
It is important that your doctor is aware of all the medications you are currently taking, including over-the-counter and prescription medications. Certain medications can affect the level of protein in your urine, so your doctor may ask you to stop taking a certain medication or to change your dose before the test.
Medications that affect protein levels in the urine include:
- antibiotics (including aminoglycosides, cephalosporins, penicillins, polymyxin B, and sulfonamides)
- antifungal medications (including amphotericin B and griseofulvin)
- penicillamine (a medication used to treat rheumatoid arthritis)
- phenazopyridine (a medication used for urinary tract pain)
- salicylates (medications used to treat arthritis)
- tolbutamide (a medication used for diabetes)
It is important that you are well hydrated before giving your urine sample. This helps make giving the urine sample easier and prevents dehydration, which can affect test results.
Avoid strenuous exercise before your test, as this can also affect the amount of protein in your urine. Finally, wait to take a protein urine test at least three days after taking a radioactive test that used contrast dye. The contrast dye used in the test is secreted in your urine and can affect results.
What Happens During the Test
Random One-Time Sample
One of the ways protein is tested in the urine is with a random, one-time sample. This may also be called a dipstick test. You may give your sample in your doctor’s office, in a medical laboratory, or at home.
You will be given a sterile container with a cap and a towellette or swab to clean around your genitals. To begin, wash your hands well and take the cap off the collection container. Do not touch the inside of the container or the cap with your fingers because they can contaminate the sample.
Clean around your urethra using the wipe or swab. Next, begin urinating into the toilet for several seconds. Stop the flow of urine, position the collection cup, and begin collecting urine midstream. It is important the cup does not touch your body because this can contaminate the sample. You should collect about two ounces of urine.
When you are finished collecting the midstream sample, continue urinating into the toilet. Replace the cap on the container and follow the instructions for returning it to your doctor or medical lab. If you are unable to return the sample within one hour after collecting it, place the sample in the refrigerator.
A 24-hour collection may be ordered if there was protein in your one-time urine sample. For this test, you will be given a large collection container and several cleansing wipes. This test will begin first thing in the morning. However, you will not collect your first urination in the morning. Instead, record the time of your first morning urination because it begins the 24-hour-collection period.
For the next 24 hours, collect all your urine in the collection cup. Be sure to clean around your urethra before urinating and do not touch the collection cup to your genitals. Between collections, store the sample in the fridge. When the 24-hour period is over, follow the instructions you were given for returning the sample.