Health Encyclopedia

Sodium urine test

Definition

The sodium urine test measures the amount of sodium the urine.

Sodium can also be measured in a blood sample.

Alternative Names

Urinary 24 hours sodium; Urine Na+

How the Test is Performed

After you provide a urine sample, it is tested in the lab. If needed, the health care provider may ask you to collect your urine at home over 24 hours. Your provider will tell you how to do this. Follow instructions exactly so that the results are accurate.

How to Prepare for the Test

Your provider will ask you to temporarily stop taking any medicines that may affect the test result. Tell your provider about all the medicines you take, including:

Corticosteroids
Nonsteroidal anti-inflammatory drugs (NSAIDs)
Prostaglandins (used to treat conditions such as glaucoma or stomach ulcers)
Water pills (diuretics)

DO NOT stop taking any medicine before talking to your provider.

How the Test will Feel

The test involves only normal urination. There is no discomfort.

Why the Test is Performed

The test is often used to help determine the cause of an abnormal sodium blood level. It also checks whether your kidneys are removing sodium from the body. It may be used to diagnose or monitor many types of kidney diseases.

Normal Results

For adults, normal urine sodium values are generally 20 mEq/L in a random urine sample and 40 to 220 mEq per day. Your result depends on how much fluid and sodium or salt you take in.

The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test result.

What Abnormal Results Mean

A higher than normal urine sodium level may be due to:

Certain medicines, such as water pills (diuretics)
Low function of the adrenal glands
Inflammation of the kidney that results in salt loss (salt-losing nephropathy)
Too much salt in the diet

A lower than normal urine sodium level may be a sign of:

Adrenal glands releasing too much aldosterone (hyperaldosteronism)
Not enough fluid in the body (dehydration)
Diarrhea and fluid loss
Heart failure
Kidney problems, such as long-term (chronic) kidney disease or kidney failure
Scarring of the liver (cirrhosis)

Risks

There are no risks with this test.

References

Kamel KS, Halperin ML. Interpretation of electrolyte and acid-base parameters in blood and urine. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 24.

Oh MS, Briefel G, Pincus MR. Evaluation of renal function, water, electrolytes, and acid-base balance. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 15.

Villeneuve P-M, Bagshaw SM. Assessment of urine biochemistry. In: Ronco C, Bellomo R, Kellum JA, Ricci Z, eds. Critical Care Nephrology. 3rd ed. Philadelphia, PA: Elsevier; 2019:chap 55.

Review Date:8/20/2023
Reviewed By:Jacob Berman, MD, MPH, Clinical Assistant Professor of Medicine, Division of General Internal Medicine, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.