The sodium urine test measures the amount of salt (sodium) in a urine sample.
Sodium can also be measured in a blood sample.
See also: Sodium - blood test
This test may be done using a random urine sample or a 24-hour urine collection.
If a 24-hour urine sample is needed:
For an infant, thoroughly wash the area around the urethra. Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on the infant. For males, place the entire penis in the bag and attach the adhesive to the skin. For females, place the bag over the labia. Diaper as usual over the secured bag.
This procedure may take a couple of attempts -- lively infants can move the bag, causing the urine to be absorbed by the diaper. Check the infant frequently and change the bag after the infant has urinated into it. Drain the urine from the bag into the container provided by your health care provider.
Deliver it to the laboratory or your health care provider as soon as possible upon completion.
Your health care provider will instruct you, if necessary, to discontinue drugs that may interfere with the test.
Drugs that can increase test measurements include:
Drugs that can decrease test measurements include:
If a 24-hour urine collection is being taken from an infant, a couple of extra collection bags may be necessary.
The test involves only normal urination, and there is no discomfort.
The test is often used to determine your hydration status and your kidney's ability to conserve or remove sodium from the urine.
Additional conditions under which the test may be performed:
Normal values are generally 40 to 220 milliequivalents per liter per day (mEq/L/day), depending on how much fluid and salt you consume.
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 doctor about the meaning of your specific test results.
Greater than normal urine sodium levels may be caused by:
Lower than normal urine sodium levels may be a sign of:
Too little or too much sodium in the diet may affect test results.
Urinary 24 hours sodium; Urine Na+
Landry DW, Bazari H. Approach to the patient with renal disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 116.
Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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