Proteinuria
 National Kidney and Urologic Diseases Information Clearinghouse 

U.S. Department 

of Health and 

Human Services 

NATIONAL 

INSTITUTES 

OF HEALTH 

What is proteinuria? 

Proteinuria—also called albuminuria or 

urine albumin—is a condition in which urine 

contains an abnormal amount of protein. 

Albumin is the main protein in the blood. 

Proteins are the building blocks for all body 

parts, including muscles, bones, hair, and 

nails. Proteins in the blood also perform a 

number of important functions. They protect 

the body from infection, help blood clot, and 

keep the right amount of fluid circulating 

throughout the body. 

As blood passes through healthy kidneys, 

they filter out the waste products and leave 

in the things the body needs, like albumin 

and other proteins. Most proteins are too 

big to pass through the kidneys’ filters into 

the urine. However, proteins from the blood 

can leak into the urine when the filters of the 

kidney, called glomeruli, are damaged. 

Proteinuria is a sign of chronic kidney disease (CKD), which can result from diabetes, 

high blood pressure, and diseases that cause 

inflammation in the kidneys. For this reason, testing for albumin in the urine is part 

of a routine medical assessment for everyone. Kidney disease is sometimes called 

renal disease. If CKD progresses, it can lead 

to end-stage renal disease (ESRD), when 

the kidneys fail completely. A person with 

ESRD must receive a kidney transplant or 

regular blood-cleansing treatments called 

dialysis. 

Who is at risk for 

proteinuria? 

People with diabetes, hypertension, or 

certain family backgrounds are at risk for 

proteinuria. In the United States, diabetes is 

the leading cause of ESRD.1 In both type 1 

and type 2 diabetes, albumin in the urine is 

one of the first signs of deteriorating kidney 

function. As kidney function declines, the 

amount of albumin in the urine increases. 

Another risk factor for developing proteinuria is hypertension, or high blood pressure. 

Proteinuria in a person with high blood pressure is an indicator of declining kidney function. If the hypertension is not controlled, 

the person can progress to full kidney failure. 

African Americans are more likely than 

Caucasians to have high blood pressure and 

to develop kidney problems from it, even 

when their blood pressure is only mildly 

elevated. In fact, African Americans are six 

times more likely than Caucasians to develop 

hypertension-related kidney failure.2 

Other groups at risk for proteinuria are 

American Indians, Hispanics/Latinos, 

Pacific Islander Americans, older adults, and 

overweight people. These at-risk groups 

and people who have a family history of 

kidney disease should have their urine tested 

regularly. 

1United States Renal Data System. USRDS 2007 

Annual Data Report. Bethesda, MD: National Institute 

of Diabetes and Digestive and Kidney Diseases, 

National Institutes of Health, U.S. Department of 

Health and Human Services; 2007. 

2Ibid. 
 

What are the signs and 

symptoms of proteinuria? 

Proteinuria has no signs or symptoms in the 

early stages. Large amounts of protein in the 

urine may cause it to look foamy in the toilet. 

Also, because protein has left the body, the 

blood can no longer soak up enough fluid, so 

swelling in the hands, feet, abdomen, or face 

may occur. This swelling is called edema. 

These are signs of large protein loss and 

indicate that kidney disease has progressed. 

Laboratory testing is the only way to find out 

whether protein is in a person’s urine before 

extensive kidney damage occurs. 

Several health organizations recommend regular urine checks for people at risk for CKD. 

A 1996 study sponsored by the National 

Institutes of Health determined that proteinuria is the best predictor of progressive 

kidney failure in people with type 2 diabetes. 

The American Diabetes Association recommends regular urine testing for proteinuria 

for people with type 1 or type 2 diabetes. 

The National Kidney Foundation recommends that routine checkups include testing 

for excess protein in the urine, especially for 

people in high-risk groups. 

What are the tests for 

proteinuria? 

Until recently, an accurate protein measurement required a 24-hour urine collection. 

In a 24-hour collection, the patient urinates 

into a container, which is kept refrigerated 

between trips to the bathroom. The patient 

is instructed to begin collecting urine after 

the first trip to the bathroom in the morning. 

Every drop of urine for the rest of the day 

is to be collected in the container. The next 

morning, the patient adds the first urination 

after waking and the collection is complete. 

Containers for a 24-hour urine collection. 

In recent years, researchers have found that 

a single urine sample can provide the needed 

information. In the newer technique, the 

amount of albumin in the urine sample is 

compared with the amount of creatinine, a 

waste product of normal muscle breakdown. 

The measurement is called a urine albuminto-creatinine ratio (UACR). A urine sample 

containing more than 30 milligrams of albumin for each gram of creatinine (30 mg/g) is 

a warning that there may be a problem. If 

the laboratory test exceeds 30 mg/g, another 

UACR test should be done 1 to 2 weeks 

later. If the second test also shows high levels of protein, the person has persistent proteinuria, a sign of declining kidney function, 

and should have additional tests to evaluate 

kidney function. 

2 Proteinuria 
 

Cup for a single urine sample. 

What additional tests for 

kidney disease may be 

needed? 

Tests that measure the amount of creatinine 

in the blood will show whether a person’s 

kidneys are removing wastes efficiently. 

Having too much creatinine in the blood is a 

sign that a person has kidney damage. The 

doctor can use the creatinine measurement 

to estimate how efficiently the kidneys are 

filtering the blood. This calculation is called 

the estimated glomerular filtration rate, or 

eGFR. CKD is present when the eGFR is 

less than 60 milliliters per minute (mL/min). 

What should a person with 

proteinuria do? 

If a person has diabetes, hypertension, or 

both, the first goal of treatment will be to 

control blood glucose, also called blood 

sugar, and blood pressure. People with diabetes should test their blood glucose often, 

follow a healthy eating plan, take prescribed 

medicines, and get the amount of exercise 

recommended by their doctor. A person 

with diabetes and high blood pressure may 

need a medicine from a class of drugs called 

angiotensin-converting enzyme (ACE) 

inhibitors or a similar class called angiotensin 

receptor blockers (ARBs). These drugs 

have been found to protect kidney function 

even more than other drugs that provide the 

same level of blood pressure control. Many 

patients with proteinuria but without hypertension may also benefit from ACE inhibitors 

or ARBs. The American Diabetes Association and the American College of Cardiology 

recommend that people with diabetes keep 

their blood pressure below 130/80.3 

People who have high blood pressure and 

proteinuria, but not diabetes, also benefit 

from taking an ACE inhibitor or ARB. 

The Joint National Committee on Prevention, Detection, Evaluation, and Treatment 

of High Blood Pressure recommends that 

people with kidney disease keep their blood 

pressure below 130/80.4 To maintain this target, a person may need to take a combination 

of two or more blood pressure medicines. A 

doctor may also prescribe a diuretic in addition to an ACE inhibitor or ARB. Diuretics 

3American Diabetes Association/American College 

of Cardiology. Hypertension in diabetes. Diabetes & 

Cardiovascular Disease Review. 2002; Issue 2. 

4National High Blood Pressure Education Program. 

The Seventh Report of the Joint National Committee on 

Prevention, Detection, Evaluation, and Treatment of High 

Blood Pressure. Bethesda, MD: National Heart, Lung, 

and Blood Institute, National Institutes of Health, U.S. 

Department of Health and Human Services; 2004. 

3 Proteinuria 
 

are also called “water pills” because they 

help a person urinate and get rid of excess 

fluid in the body. 

In addition to blood glucose and blood pressure control, the National Kidney Foundation recommends restricting dietary salt and 

protein. A doctor may refer a patient to a 

dietitian to help develop and follow a healthy 

eating plan. 

Points to Remember 

•	 Proteinuria is a condition in which urine 

contains a detectable amount of protein. 

•	 Proteinuria is a sign of chronic kidney 

disease (CKD). 

•	 Groups at risk for proteinuria include 

African Americans, American Indians, 

Hispanics/Latinos, Pacific Islander 

Americans, older people, overweight 

people, people with diabetes or hypertension, and people who have a family 

history of kidney disease. 

•	 Proteinuria may have no signs or symptoms. Laboratory testing is the only 

way to find out whether protein is in a 

person’s urine. 

•	 Several health organizations recommend regular checks for proteinuria 

so kidney disease can be detected and 

treated before it progresses. 

•	 A person with diabetes, hypertension, 

or both should work to control blood 

glucose and blood pressure. 

Hope through Research 

In recent years, researchers have learned 

much about kidney disease. The National 

Institute of Diabetes and Digestive and 

Kidney Diseases (NIDDK) sponsors several 

programs aimed at understanding kidney 

failure and finding treatments to stop its 

progression. 

The NIDDK’s Division of Kidney, Urologic, 

and Hematologic Diseases supports basic 

research into normal kidney function and 

the diseases that impair normal function at 

the cellular and molecular levels, including 

diabetes, high blood pressure, glomerulonephritis, and other diseases marked by 

proteinuria. 

Participants in clinical trials can play a more 

active role in their own health care, gain 

access to new research treatments before 

they are widely available, and help others by 

contributing to medical research. For information about current studies, visit 

www.ClinicalTrials.gov. 

4 Proteinuria 
5 Proteinuria

National Kidney Disease 

Education Program 

3 Kidney Information Way 

Bethesda, MD 20892 

Phone: 1–866–4–KIDNEY (454–3639) 

TTY: 1–866–569–1162 

Fax: 301–402–8182 

Email: nkdep@info.niddk.nih.gov 

Internet: www.nkdep.nih.gov

The National Kidney Disease Education 

Program (NKDEP) is an initiative of the 

National Institute of Diabetes and Digestive 

and Kidney Diseases, National Institutes 

of Health, U.S. Department of Health and 

Human Services. The NKDEP aims to 

raise awareness of the seriousness of kidney 

disease, the importance of testing those at 

high risk, and the availability of treatment to 

prevent or slow kidney disease.

For More Information

American Kidney Fund 

6110 Executive Boulevard, Suite 1010 

Rockville, MD 20852 

Phone: 1–800–638–8299 or 301–881–3052 

Email: helpline@kidneyfund.org

Internet: www.kidneyfund.org

National Kidney Foundation 

30 East 33rd Street 

New York, NY 10016 

Phone: 1–800–622–9010 or 212–889–2210 

Internet: www.kidney.org

Acknowledgments

Publications produced by the Clearinghouse 

are carefully reviewed by both NIDDK 

scientists and outside experts. This publication was originally reviewed by Lee A. 

Hebert, M.D., Ohio State University. Jeanne 

Charleston, R.N., and Edgar Miller, M.D., 

both of the Johns Hopkins Medical Institutions, Baltimore, reviewed the updated 

version of the publication.

You may also find additional information about this 

topic by visiting MedlinePlus at www.medlineplus.gov.

This publication may contain information about medications. When prepared, this publication included

the most current information available. For updates 

or for questions about any medications, contact 

the U.S. Food and Drug Administration toll-free at 

1–888–INFO–FDA (463–6332) or visit www.fda.gov. 

Consult your doctor for more information.
National Kidney and 

Urologic Diseases 

Information Clearinghouse 

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Phone: 1–800–891–5390 

TTY: 1–866–569–1162 

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Email: nkudic@info.niddk.nih.gov 

Internet: www.kidney.niddk.nih.gov 

The National Kidney and Urologic Diseases 

Information Clearinghouse (NKUDIC) is a 

service of the National Institute of Diabetes 

and Digestive and Kidney Diseases (NIDDK). 

The NIDDK is part of the National Institutes 

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and Human Services. Established in 1987, the 

Clearinghouse provides information about 

diseases of the kidneys and urologic system to 

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This fact sheet is also available at 

www.kidney.niddk.nih.gov. 

U.S. DEPARTMENT OF HEALTH 

AND HUMAN SERVICES 

National Institutes of Health 

NIH Publication No. 09–4732 

March 2009