Albuminuria (proteinuria)

Tests and procedures Urine tests Urine albumin-creatinine ratio (uACR)

Last Updated: July 19, 2023

Medically reviewed by NKF Patient Education Team

Albuminuria (sometimes referred to as proteinuria) is when you have albumin in your urine.

Table of Contents

About albuminuria (proteinuria)

Albuminuria (sometimes referred to as proteinuria) is when you have albumin in your urine. Albumin is an important protein normally found in the blood that serves many roles in the body - building muscle, repairing tissue, and fighting infection. It is not usually found in the urine.

Healthy kidneys stop most of your albumin from getting through their filters and entering the urine. There should be very little or no albumin in your urine. If your kidneys are damaged, albumin can “leak” through their filters and into your urine.

Source: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Albuminuria (proteinuria) is not a separate disease. It is a symptom of many different types of kidney disease and a significant risk factor for complications. Having albumin in your urine can be a sign of kidney disease, even if your estimated glomerular filtration rate (eGFR) is above 60 or “normal”.

Albuminuria (proteinuria) is not a separate disease. It is a symptom of many different types of kidney disease and a significant risk factor for complications.

Signs and symptoms

Most people with albuminuria (proteinuria) may not notice any symptoms. This is why it is so important to get regular health checkups (including lab tests), especially if you have any risk factors for albuminuria or kidney disease.

If symptoms are present, you may notice one or more of the following:

  • Foamy urine
  • Puffiness around the eyes (especially in the morning)
  • Frequent urination (peeing more often than usual)
  • Swelling of your feet, ankles, belly area, or face

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Causes

Albuminuria (proteinuria) is caused by kidney damage, specifically when the damage occurs in the glomerulus (the kidney’s filter). Sometimes this is temporary (short-term damage), while other times it is chronic (long-term damage). The exact cause for the kidney damage is different for each person and may even be due to several factors combined.

Some of the most common causes of temporary (short-term) albuminuria include:

  • Dehydration (not drinking enough water)
  • High-intensity exercise
  • Fever and/or infection
  • Heart failure exacerbation (flare-up)

Some of the most common causes of chronic (long-term) albuminuria include:

Having albuminuria may not always mean you have actual kidney damage. This is why repeat testing is so important – to help tell the difference between chronic (long-term) kidney damage and temporary (short-term) stress on the kidneys.

Having albuminuria may not always mean you have actual kidney damage. This is why repeat testing is so important – to help tell the difference between chronic (long-term) kidney damage and temporary (short-term) stress on the kidneys.

Types

You may have heard or read about the words “microalbuminuria” and “macroalbuminuria”. These words were used in the past to help describe categories for how high a person’s urine albumin-creatinine ratio (uACR) level is. However, these separate words are no longer recommended - they add confusion without providing any extra benefit. Newer research has shown that any uACR level above the goal range is a risk factor for complications. Any level above 30 mg/g is now called “albuminuria” (instead of using two separate terms).

Complications

Albuminuria is a significant risk factor for developing complications. Some of these complications include:

Your risk for getting these complications is directly connected with your uACR level. This means a higher uACR level comes with a higher risk for developing one or more of these complications. Getting your uACR level down will help lower your risk for complications, even if you are not able to get your uACR level into the goal range.

Diagnosis

Urine albumin-creatinine ratio (uACR)

The primary way to diagnose albuminuria is through a urine test called the urine albumin-creatinine ratio (uACR). Your uACR results help describe the degree of albuminuria you may be experiencing, if any.

A lower number is better for this test, ideally lower than 30. A value of 30 or higher suggests you may be at a higher risk for complications. The higher your number, the higher your risk.

The quantitative uACR test is the most preferred initial test for adults at high risk for kidney disease because it offers the most precision while also being convenient. The National Kidney Foundation supports semi-quantitative uACR testing for adults at increased risk for kidney disease when access to quantitative testing is limited. Semi-quantitative tests offer less precision but more convenience since they can be done at home or in a doctor’s office. A positive result on a semi-quantitative test should be confirmed with a quantitative test.

It is important to emphasize that this test often needs to be repeated one or more times to confirm the results. Decisions are rarely made based on the results of one test.

Lower than 30 mg/g

  • A result in this range is considered “normal” or “at goal”.
  • This result puts you at the lowest risk for getting kidney failure or having a cardiovascular event (heart attack or stroke) because of albuminuria.
  • You may be asked to repeat this test within 3 to 6 months to confirm your results are accurate.

30 to 299 mg/g

  • A uACR in this range is considered “moderately increased”.
  • If you have not previously had a result in this range, you will likely be asked to repeat this test within 3 to 6 months to confirm your results are accurate.
  • Having a confirmed result in this range puts you at a higher risk for getting kidney failure or having a cardiovascular event (heart attack or stroke).
  • Having a confirmed result in this range twice in 3-6 months may mean you have kidney disease (even if your eGFR is above 60).

300 mg/g or higher

  • A uACR in this range is considered “severely increased”.
  • If you have not previously had a result in this range, you will likely be asked to repeat this test within 3 to 6 months to confirm your results are accurate.
  • Having a confirmed result in this range puts you at a significantly higher risk for getting kidney failure or having a cardiovascular event (heart attack or stroke).
  • Having a confirmed result in this range twice in 3-6 months may mean you have kidney disease (even if your eGFR is above 60).

 

Other tests

If your uACR is much higher than the target range, extra tests may be recommended to get more information about what may be causing your albuminuria. These tests may include:

  • Kidney biopsy - especially if there is a concern for glomerular disease. This test can help find out what caused your kidney disease and how much damage to the kidneys has already happened.
  • Imaging tests - especially if there is a concern for kidney cancer, kidney stones, or structural problems within the kidney. These tests include things like an ultrasound or CT scan. These produce a picture of your kidneys and urinary tract.

Treatment

Overview

The main goal of treatment is to lower your overall risk for developing complications. This starts with addressing the most likely cause for your albuminuria (proteinuria). For most people, the initial focus will likely be on getting your blood pressure and/or blood sugar levels into their target ranges. A combination of lifestyle modifications and medication is generally the most effective approach for treating albuminuria and lowering your risk for complications.

The main goal of treatment is to lower your overall risk for developing complications, starting with targeting the most likely cause for your albuminuria.

Medications

Medications that help you manage your high blood pressure and/or diabetes (if applicable) are usually the first step. Medications that work directly in the kidneys to help decrease the amount of pressure placed on your glomeruli (the filters in your kidney) are also usually recommended. These medications are commonly known as “kidney protective” because they can help keep your glomeruli (filters in your kidneys) healthy and lower uACR levels.

 

Angiotensin converting enzyme (ACE) inhibitors or angiotensin-receptor blockers (ARBs)

  • Available for use in the US since the early 1980s.
  • ACE inhibitors have generic names ending in “-pril”. Examples include benazepril (Lotensin), lisinopril (Zestril, Prinivil), quinapril (Accupril), and ramipril (Altace).
  • ARBs have generic names ending in “-sartan”. Examples include irbesartan (Avapro), losartan (Cozaar), olmesartan (Benicar), and valsartan (Diovan).
  • Usually the most preferred starting treatment for albuminuria.
  • Most are available as low-cost generic options.
  • People should not mix medications from these classes. In other words, use an ACE inhibitor OR an ARB, not both together.
  • More information can be found on the ACE inhibitors & ARBs page.

Sodium-glucose cotransporter-2 (SGLT2) inhibitors

  • Available for use in the US since the early 2010s.
  • SGLT2 inhibitors have generic names ending in “-flozin”. Examples include canagliflozin (Invokana), dapagliflozin (Farxiga), and empagliflozin (Jardiance).
  • These medicines were originally developed to help lower blood sugar levels in people with diabetes. Later studies found they also offer kidney protection benefits. 
  • Some SGLT2 inhibitors are also FDA-approved for use in people with chronic kidney disease and/or heart failure, even if they do not have type 2 diabetes (usually at lower doses). This does not apply to all SGLT2 inhibitors.
  • Currently, there are no generic SGLT2 inhibitor options approved for use in the US.
  • More information can be found on the SGLT2 inhibitors page.

Non-steroidal mineralocorticoid receptor antagonists (nsMRAs)

  • Available for use in the US since the early 2020s.
  • The only nsMRA available in the US is finerenone (Kerendia).
  • This medicine is only FDA-approved for people who have albuminuria AND type 2 diabetes. The effects of this medicine in people without diabetes is being tested in clinical trials.
  • Currently, there are no generic nsMRA options approved for use in the US.
  • More information can be found on the nsMRAs page.

 

 

Nutrition

Ask your kidney dietitian, diabetes care & education specialist, or healthcare provider about your nutritional needs. Fortunately, the steps you may already be taking to help manage any other health conditions you may have (high blood pressure, diabetes, heart failure) can help with albuminuria too.

For general guidance on nutrition, click the link that best matches your situation:

Exercise

Regular exercise is important for a healthy lifestyle. For general guidance on exercise recommendations, visit the Staying fit with kidney disease page.

Other steps

Some additional steps that can help you lower your uACR levels and lower your risk for a cardiovascular event (heart attack or stroke) include (not all recommendations will apply to everybody):

Questions to Ask

 

  • When was the last time I had a uACR test?
  • What were the results of my last uACR test?
  • What steps can I take today to lower my uACR level into the goal range and lower my risk of complications?
  • What are my other risk factors for having a cardiovascular event in the future?
  • What actions can I take today to improve my kidney health and decrease my cardiovascular risk?

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This content is provided for informational use only and is not intended as medical advice or as a substitute for the medical advice of a healthcare professional.
© 2024 National Kidney Foundation, Inc.