Content updated on August 24, 2021 - Medically reviewed by our Medical Advisory Committee

When your kidneys are not working as well as they should, protein can leak through your kidney’s filters and into your urine (i.e., your pee). Protein in your urine is called proteinuria or albuminuria. It is a sign that your kidneys are damaged.

What does protein in the urine mean?

Protein is normally found in your blood. The main protein in your blood is called albumin. Proteins have many important jobs in your body. For example, they help build your bones and muscles, prevent infection and control the amount of fluid in your blood.

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What causes protein in the urine?

Healthy kidneys remove extra fluid and waste from your blood and transform it into urine. Healthy kidneys do not remove proteins and other important nutrients, which pass through and return to your blood. But when your kidneys are damaged, they may let this protein leak into your urine. This causes high levels of protein in your urine.

Anyone can have protein in their urine. You may be more likely to have protein in your urine if you have one or more of the risk factors for kidney disease. There are health problems that can cause long-lasting protein in the urine, and some that can cause short-term protein in the urine.

Causes of long-lasting protein in the urine

Health problems that may cause long-lasting high levels of protein in the urine include:

Causes of short-term protein in the urine

Health problems that may cause a short-term high level of protein in the urine include:
Dehydration (not having enough water in your body)
High stress
Being in very cold temperatures
Fever
High-intensity physical activity

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What are the symptoms of protein in the urine?

When your kidneys have only mild damage and you have only small levels of protein in your urine, you will not notice any symptoms.

When your kidneys have more severe damage and you have high levels of protein in your urine, you may start to notice symptoms such as:

  • Foamy, frothy or bubbly urine
  • Swelling in your hands, feet, belly or face
  • Urinating more often
  • Feeling sick to your stomach or throwing up
  • Muscle cramps at night

If you have any of these symptoms, talk to your doctor right away.

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How will I know if I have protein in my urine?

The only way to know if you have protein in your urine is to have a urine test. The test will measure the levels of protein in your urine.

The name of the urine test that measures the level of albumin in your urine is called the urine albumin-to-creatinine ratio (UACR). A UACR compares the level of albumin to the level of creatinine (a waste product in your blood that comes from your muscles). A normal UACR is less than 30mg/g. If your UACR is 30 mg/g or higher, it can be a sign of kidney disease, and you should ask your doctor if you should have other tests for kidney disease.

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How do doctors treat protein in the urine?

Doctors treat the cause of protein in the urine:

  • If you have diabetes, your doctor will help create a treatment plan to keep it under control and slow down damage to your kidneys. They may recommend that you:
    • Check your blood sugar often
    • Take certain medicines
    • Follow a diabetes-friendly eating plan
    • Be active most days of the week
  • If you have high blood pressure, your doctor may prescribe a medicine to help lower your blood pressure and slow down damage to your kidneys. The types of medicine are:
    • Angiotensin-converting enzyme (ACE) inhibitors, which are a group of medicines that lower blood pressure. They widen your blood vessels, help your kidneys get rid of extra water and lower the hormones that raise blood pressure.
    • Angiotensin receptor blockers (ARBs), which are a group of medicines that lower blood pressure. They widen your blood vessels.
  • If you do not have diabetes or high blood pressure, your doctor may still prescribe an ACE inhibitor or an ARB to slow down damage to your kidneys.

Drinking water will not treat the cause of protein in your urine unless you are dehydrated. Drinking water will dilute your urine (water down the amount of protein and everything else in your urine), but will not stop the cause of your kidneys leaking protein.

If you have protein in your urine, talk with your doctor to choose the best treatment option for you.

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