High protein levels in urine can develop if your kidneys are not functioning correctly. Causes can include dehydration and kidney disease. Treatment and support is available.

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Your kidneys are essential because they filter your blood. They contain tiny blood vessels called glomeruli, which remove waste products via the urine and reabsorb protein that stays in the blood.

If your kidneys stop filtering your blood, high protein levels can develop in your urine, also known as proteinuria.

Proteinuria can result from chronic conditions like kidney disease or damage from high blood pressure or diabetes. It can also be temporary due to an unbalanced diet, intense exercise, or dehydration.

Let’s explore the possible causes of proteinuria, along with its symptoms and treatment.

You likely won’t have any symptoms in the early stages of kidney damage. That’s because there are only small amounts of protein in your urine.

As kidney damage progresses, more protein will pass into your urine. This may cause symptoms such as:

If you have proteinuria, it may be a good idea to take note of your other symptoms. They may help a doctor identify the underlying cause, which can include:

Dehydration

Dehydration happens when your body loses too much fluid. It’s a common, temporary cause of proteinuria.

Your body uses water in the blood to deliver nutrients like proteins and waste products to the kidneys. Without enough fluid, it’ll have difficulty delivering nutrients. Without enough fluid, the kidneys can’t filter the blood properly, so protein ends up in urine instead of returning to the bloodstream.

High blood pressure

High blood pressure, or hypertension, can weaken the blood vessels in the kidneys. This decreases their ability to reabsorb protein, which then flows into the urine.

Since high blood pressure develops slowly, you may not have symptoms for years. It can cause headaches, shortness of breath, or nosebleeds if it becomes severe.

Diabetes

Diabetes is a metabolic disorder that causes high levels of blood sugar. There are multiple types of diabetes, including type 1 and type 2 diabetes.

With diabetes, high blood sugar can damage the blood vessels in the kidneys, allowing protein to leak into the urine. This can be an early sign of diabetic kidney damage.

Glomerulonephritis

Proteinuria may indicate glomerulonephritis, or inflammation of the glomeruli.

Usually, when the glomeruli filter blood, they reabsorb protein. However, if the glomeruli are damaged, protein can pass through and enter the urine.

Glomerulonephritis may also cause hematuria, or red blood cells in the urine. Hematuria can make urine look pink or cola-colored.

Chronic kidney disease

Chronic kidney disease (CKD) is the progressive loss of kidney function. It may cause proteinuria in the early stages, but it usually doesn’t cause noticeable symptoms.

If CKD progresses, it can result in kidney failure, which can be life threatening if left untreated.

Symptoms of kidney failure to look out for include:

Autoimmune diseases

The immune system usually produces antibodies, also known as immunoglobulins, that fight foreign organisms. If you have an autoimmune disease, the immune system makes antibodies that attack the body’s tissues. These substances are called autoantibodies.

If the autoantibodies damage the glomeruli, inflammation can occur. This leads to kidney damage and, eventually, proteinuria.

The following autoimmune diseases have associations with proteinuria:

Preeclampsia

In preeclampsia, a pregnant person develops high blood pressure at or after 20 weeks of pregnancy. This temporarily impairs the kidneys’ ability to filter protein, which causes proteinuria.

Though preeclampsia usually goes away after delivery, it’s a serious condition that can lead to preterm birth. Individuals with preeclampsia require careful monitoring.

Cancer

In severe cases, proteinuria is due to cancer. Several types of cancer have associations with high urine protein levels, including:

A 2023 study found that the inflammatory effect of renal cell cancer can alter kidney function.

In some conditions, such as multiple myeloma, kidney damage occurs when abnormal proteins in the blood bind with normal proteins in the urine. As kidney function declines, more protein ends up in the urine.

Other causes of proteinuria include:

  • dysfunction that affects the renal tubules
  • inflammation of the urinary tract, which may be the result of a condition such as a urinary tract infection or tumor
  • overproduction of certain proteins
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There are several different types of proteinuria, including:

  • glomerular
  • tubular
  • overflow
  • post-renal

Glomerular proteinuria is the most common type. Albuminuria, or excess amounts of the protein albumin, is a subtype of glomerular proteinuria and could indicate kidney disease.

If you have temporary or mild proteinuria, you likely won’t need treatment. If you have consistent proteinuria, you’ll need to treat the underlying condition.

Treatment may include:

  • Dietary changes: If you have kidney disease, diabetes, or high blood pressure, a doctor will recommend specific diet changes.
  • Weight management: Maintaining a moderate weight may help you manage conditions that impair kidney function.
  • Diabetes medication: You may need oral medication or insulin therapy to help you manage high blood sugar.
  • Dialysis: In glomerulonephritis and kidney failure, dialysis helps manage high blood pressure and fluid imbalances.
  • Blood pressure medication: If you have high blood pressure, a doctor might prescribe medication to help lower your blood pressure.

Learn more about the link between high blood pressure and diabetes.

The only way to diagnose proteinuria is through a urine test, which measures the amount of protein in your urine.

You will have the test in a doctor’s office. During the procedure, you urinate into a specimen cup. The doctor places a dipstick, or a small plastic stick coated with chemicals, into the urine sample. If it has too much protein, the stick will change color.

They will send the rest of the urine to a lab for examination under a microscope.

If the doctor thinks you have kidney concerns, they’ll repeat the urine test three times in 3 months. This helps them rule out temporary causes of proteinuria.

A doctor might also use the following tests to determine what’s causing your proteinuria:

  • 24-hour urine protein test: In this test, the doctor collects multiple urine samples over 1 day and sends them to a lab.
  • Glomerular filtrate rate (GFR) blood test: This test checks your kidney function.
  • Kidney biopsy: During a biopsy, a doctor removes a sample of your kidney and examines it for any signs of kidney damage.
  • Imaging tests: You may receive an ultrasound or a CT scan, which takes detailed photos of your kidneys and urinary tract.
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Some people are more likely to develop proteinuria than others. Common risk factors include:

  • Age: Older adults tend to experience dehydration and kidney concerns more often. Pregnant people ages 40 years and older have a greater risk of preeclampsia.
  • High blood pressure: People with high blood pressure have a higher risk of developing diabetes and kidney disorders.
  • Diabetes: Diabetes is the most common cause of CKD. It also has associations with preeclampsia and glomerulonephritis.
  • Family history: You’re more likely to develop proteinuria if you have a family history of kidney disease or preeclampsia.
  • A higher body weight: High blood pressure, diabetes, and preeclampsia have associations with overweight or obesity.

In general, Black or African Americans and Hispanic and Latin@s have a higher risk of developing kidney disease compared to white Americans.

Proteinuria can be temporary, so some people won’t require treatment.

However, proteinuria often means that your kidneys aren’t filtering blood properly. Therefore, treatment aims to manage any underlying conditions you may have.

If necessary, a doctor can create a treatment plan to help protect your kidneys and ease any related symptoms.