Calcium - urine

Definition

This test measures the amount of calcium in the urine. All cells need calcium in order to work. Calcium helps build strong bones and teeth. It is important for heart function, and helps with muscle contraction, nerve signaling, and blood clotting.

See also: Calcium - blood

Alternative Names

Urinary Ca+2; Kidney stones - calcium in urine; Renal calculi - calcium in your urine; Parathyroid - calcium in urine

How the Test is Performed

A 24-hour urine sample is most often needed:

For an infant, thoroughly wash the area where urine exits the body.

This procedure may take a few tries. An active baby can move the bag, causing urine to go into the diaper. You may need extra collection bags.

Check the infant often 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 the sample to the laboratory or to your provider as soon as possible.

How to Prepare for the Test

Many medicines can interfere with urine test results.

How the Test will Feel

The test involves only normal urination, and there is no discomfort.

Why the Test is Performed

Urine calcium level can help your provider:

Normal Results

If you are eating a normal diet, the expected amount of calcium in the urine is 100 to 300 milligrams per day (mg/day) or 2.50 to 7.50 millimoles per 24 hours (mmol/24 hours). If you are eating a diet low in calcium, the amount of calcium in the urine will be 50 to 150 mg/day or 1.25 to 3.75 mmol/24 hours.

Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What Abnormal Results Mean

A high level of urine calcium (above 300 mg/day) may be due to:

A low level of urine calcium may be due to:

References

Bringhurst FR, Demay MB, Kronenberg HM. Hormones and disorders of mineral metabolism. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 29.

Klemm KM, Klein MJ, Zhang Y. Biochemical markers of bone metabolism. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 16.

Thakker RV. The parathyroid glands, hypercalcemia, and hypocalcemia. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 227.



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.
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