What is a urine protein test?

A urine protein test measures the amount of protein present in urine. Healthy people don’t have a significant amount of protein in their urine. However, protein may be excreted in the urine when the kidneys aren’t working properly or when high levels of certain proteins are present in the bloodstream.

Your doctor may collect a urine test for protein as a random one-time sample or every time you urinate over a 24-hour period.

Your doctor may order this test if they suspect a problem with your kidneys. They also may order the test:

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:

Certain people are more at risk for developing kidney problems. Your doctor may order regular urine protein testing to 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, or Hispanic descent
  • being overweight
  • being older

It’s important that your doctor knows all the medications you’re 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 medication or to change your dose before the test.

Medications that affect protein levels in the urine include:

  • antibiotics, such as aminoglycosides, cephalosporins, and penicillins
  • antifungal medications, such as amphotericin-B and griseofulvin (Gris-PEG)
  • lithium
  • nonsteroidal anti-inflammatory drugs (NSAIDs)
  • penicillamine (Cuprimine), a medication used to treat rheumatoid arthritis
  • salicylates (medications used to treat arthritis)

It’s important that you’re well-hydrated before giving your urine sample. This makes 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. You should also wait to take a urine protein 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.

Random, one-time sample

A random, one-time sample is one way protein is tested in the urine. This is also called a dipstick test. You may give your sample in your doctor’s office, a medical laboratory, or at home.

You’ll be given a sterile container with a cap and a towelette or swab to clean around your genitals. To begin, wash your hands well and take the cap off the collection container. Don’t touch the inside of the container or the cap with your fingers, or you may 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 under you, and begin collecting urine midstream. Don’t let the container touch your body, or you may contaminate the sample. You should collect about 2 ounces of urine. Learn more about how to collect a sterile sample for this type of urine test.

When you’re 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’re unable to return the sample within one hour of collecting it, place the sample in the refrigerator.

24-hour collection

Your doctor may order a 24-hour collection if there was protein in your one-time urine sample. For this test, you’ll be given a large collection container and several cleansing wipes. Don’t collect your first urination of the day. However, record the time of your first urination because it will begin 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 don’t touch the collection cup to your genitals. Store the sample in your refrigerator between collections. When the 24-hour period is over, follow the instructions you were given for returning the sample.

Your doctor will evaluate your urine sample for protein. They may want to schedule another urine protein test if your results show you have high levels of protein in your urine. They may also want to order other lab tests or physical examinations.