CALCIUM BLOOD TEST

Calcium blood test  

The calcium blood test measures the level of calcium in the blood. 

Your body requires calcium to maintain healthy bones and teeth. It’s also essential for keeping your nerves, heart, and muscles functioning properly. Since calcium is so important for many of your body’s functions, its levels need to be within a tight range.

How should you prepare?

Your health care provider may tell you to temporarily stop taking certain medicines that can affect the test. These medicines may include:

• Calcium salts (may be found in nutritional supplements or antacids)
• Lithium
• Thiazide diuretics (water pills)
• Thyroxine
• Vitamin D

Why the Test is Performed

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 signalling, and blood clotting.

Your doctor may order this test if you have signs or symptoms of:

• Certain bone diseases
• Certain cancers, such as multiple myeloma, a cancer of the breast, lung, neck, and kidney
• Chronic kidney disease
• Chronic liver disease
• Disorders of the parathyroid glands (hormone made by these glands controls calcium and vitamin D levels in the blood)
• Disorders that affect how your intestines absorb nutrients
• Overactive thyroid gland or taking too much thyroid hormone medicine
• Abnormal vitamin D level

Your doctor may also order this test if you have been on bed rest for a long time.

How to interpret the results

Normal values range from 8.5 to 10.2 mg/dL (2.13 to 2.55 millimole/L).

Talk to your doctor about the meaning of your specific test results.

 

High total calcium levels can be caused by

A higher than the normal level may be due to a number of health conditions. Common causes include:

• Being on bed rest for a long time.
• Consuming too much calcium or vitamin D.
• Hyperparathyroidism 
• Infections that cause granulomas such as tuberculosis and certain fungal and mycobacterial infections.
• Multiple myeloma
• Metastatic bone tumor 
• Overactive thyroid gland (hyperthyroidism) or too much thyroid hormone replacement medicine.
• Paget disease. Abnormal bone destruction and regrowth, causing deformity of the affected bones.
• Sarcoidosis. Lymph nodes, lungs, liver, eyes, skin, or other tissues become swollen or inflamed.
• Tumors producing a parathyroid hormone-like substance.
• Use of certain medicines such as lithium, tamoxifen, and thiazides.

Low total calcium levels can be caused by

• Disorders that affect absorption of nutrients from the intestines
• Hypoparathyroidism (parathyroid glands do not make enough of their hormone)
• Kidney failure
• Low blood level of albumin
• Liver disease
• Magnesium deficiency
• Pancreatitis
• Vitamin D deficiency