A calcium in urine test measures the amount of calcium in your urine. Calcium is one of the most important minerals in your body. You need calcium for healthy bones and teeth. Calcium is also essential for proper functioning of your nerves, muscles, and heart. Almost all of your body's calcium is stored in your bones. A small amount circulates in the blood, and the remainder is filtered by the kidneys and passed into your urine. If urine calcium levels are too high or too low, it may mean you have a medical condition, such as kidney disease or kidney stones. Kidney stones are hard, pebble-like substances that can form in one or both kidneys when calcium or other minerals build up in the urine. Most kidney stones are formed from calcium.

Too much or too little calcium in the blood can also indicate a kidney disorder, as well as certain bone diseases, and other medical problems. So if you have symptoms of one of these disorders, your health care provider may order a calcium blood test, along with a calcium in urine test. In addition, a calcium blood test is often included as part of a regular check-up.

Other names: urinalysis (calcium)

You may need a calcium in urine test if you have symptoms of a kidney stone. These symptoms include:

• Severe back pain
• Abdominal pain
• Nausea and vomiting
• Blood in the urine
• Frequent urination

You may also need a calcium in urine test if you have symptoms of a parathyroid disorder.

Symptoms of too much parathyroid hormone include:

• Nausea and vomiting
• Loss of appetite
• Abdominal pain
• Fatigue
• Frequent urination
• Bone and joint pain

Symptoms of too little parathyroid hormone include:

• Abdominal pain
• Muscle cramps
• Tingling fingers
• Dry skin
• Brittle nails

You'll need to collect all your urine during a 24-hour period. This is called a 24-hour urine sample test. Your health care provider or a laboratory professional will give you a container to collect your urine in and instructions on how to collect and store your samples. A 24-hour urine sample test generally includes the following steps:

• Empty your bladder in the morning and flush that urine down. Do not collect this urine. Record the time.
• For the next 24 hours, save all your urine in the container provided.
• Store your urine container in a refrigerator or a cooler with ice.
• Return the sample container to your health provider's office or the laboratory as instructed.

If your results show higher than normal calcium levels in your urine, it may indicate:

• Risk for or the presence of a kidney stone
• Hyperparathyroidism, a condition in which your parathyroid gland produces too much parathyroid hormone
• Sarcoidosis, a disease that causes inflammation in the lungs, lymph nodes, or other organs
• Too much calcium in your diet from vitamin D supplements or milk

If your results show lower than normal calcium levels in your urine, it may indicate:

• Hypoparathyroidism, a condition in which your parathyroid gland produces too little parathyroid hormone
• Vitamin D deficiency
• A kidney disorder

If your calcium levels are not normal, it doesn't necessarily mean you have a medical condition needing treatment. Other factors, such as diet, supplements, and certain medicines, including antacids, can affect your urine calcium levels. If you have questions about your results, talk to your health care provider.

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