Urinary Calcium Excretion - Calcium in Urine

Overview & Description

This test measures the amount of calcium in urine.
Calcium is needed for many cellular functions. It is especially important for bone structure and muscle activity. The amount of calcium in urine can help find and monitor disorders involving calcium regulation.

Who is a candidate for the test?

This test is ordered to help diagnose diseases of the kidneys, parathyroid glands, or bones.

How is the test performed?

This test is performed on a urine sample collected over 24 hours.
In general, this schedule is followed: On the first day, the person should urinate as usual after getting up. This sample is not saved. Then all urine produced for the next 24 hours is collected in a special container. The next morning's urine is added to the day's collection. The sample must be refrigerated until it is delivered to a healthcare provider.

---

Preparation & Expectations

What is involved in preparation for the test?

A healthcare provider provides specific instructions. Generally, no special preparation is required.

---

Results and Values

What do the test results mean?

Normal levels of calcium in urine range from 100 to 300 milligrams per day for persons on a normal diet. For those on a low-calcium diet, from 50 to 150 milligrams per day is normal.
Abnormally high levels of calcium in the urine may indicate:

Cushing's syndrome, which is an excess of hormones known as corticosteroids

idiopathic hypercalcemia, which is an elevated calcium level in the blood with no known cause

milk-alkali syndrome, which is an increased blood calcium level caused by ingesting large amounts of calcium and antacids

osteolytic bone disease, which is any disease that destroys bone

osteoporosis, a thinning of the bones that commonly occurs in the elderly

primary hyperparathyroidism, which is excess activity of the parathyroid gland that causes increased blood calcium levels

renal tubular acidosis, a metabolic defect of the kidneys

sarcoidosis, a disease, thought to be caused by an abnormal immune system, that causes problems in multiple areas of the body but especially the lungs

vitamin D intoxication

Abnormally low levels of calcium may indicate:

hypoparathyroidism, or low activity of the parathyroid gland

malabsorption disorders

renal osteodystrophy or thinning of bones caused by kidney failure

vitamin D deficiency

---

Attribution

Author:David T. Moran, MD
Date Written:
Editor:Evans, Gwen, BA
Edit Date:03/18/00
Reviewer:Adam Brochert, MD
Date Reviewed:09/19/01