Calcium, Serum

When your test result values fall below the reference range, they’re considered low. Having a low blood calcium level is called hypocalcemia.

The prefix “hypo-” means “low” or “not enough.” Hypocalcemia means you have lower-than-normal levels of calcium in your blood.

Typically, hypocalcemia occurs when either too much calcium is lost through your urine or when not enough calcium is moved from your bones into your blood.

Symptoms of low calcium levels include:

- cramps in your abdomen or muscles

- a tingling sensation in your fingers

- irregular heartbeat

Your doctor may treat hypocalcemia through the use of calcium supplements and sometimes vitamin D supplements. If there’s an underlying disease or condition that’s causing your hypocalcemia, they’ll work to identify and treat that as well.

Some of the potential causes of hypocalcemia include:

- Certain medications, including corticosteroids, anticonvulsants, and rifampin (an antibiotic)

- Deficiency of calcium or vitamin D in your diet

- Hypoparathyroidism (an underactive parathyroid gland)

- Increased levels of phosphorus [Elevated phosphate levels also inhibit 1-alpha hydroxylase, a renal enzyme required for activation of Vitamin D. The decrease of active vitamin D results in decreased intestinal absorption of calcium, decreased renal calcium and phosphate reabsorption, and impaired bone mineralization.]

- Inherited resistance to the effects of parathyroid hormone

- Kidney failure [in chronic kidney disease (=CKD), the kidneys are less able to make active vitamin D. Without enough active vitamin D, you absorb less calcium from the food you eat, so it then becomes low in your blood.]

- Low levels of albumin in the blood [possibly due to malnutrition or liver disease, in which the total calcium level may or may not reflect a truly hypocalcemic state. Low albumin levels can also be due to malabsorption syndromes, or malnutrition. Also, low albumin is very common if you are acutely ill. With low albumin, only the bound calcium is low. Ionized calcium remains normal, and calcium metabolism is being regulated appropriately.]

- Magnesium deficiency [Normally, the parathyroid glands release a hormone that increases blood calcium levels when they are low. Magnesium is required for the production and release of parathyroid hormone, so when magnesium is too low, insufficient parathyroid hormone is produced and blood calcium levels are also reduced (hypocalcemia).]

- Pancreatitis (inflammation of the pancreas)

- Problems with absorption of calcium

- Renal failure

If your calcium blood test results reveal that you have high or low levels of calcium, it doesn't necessarily mean that you have a medical condition. Other factors, such as diet and certain medications, can affect your calcium levels. There could’ve also been an error in the collection, transport or processing of the test

Test result values that fall above the reference range are considered high. Having a higher-than-normal blood calcium level is called hypercalcemia.

In the medical world, the prefix “hyper-” means “high” or “too much.” Hypercalcemia means you have higher-than-normal calcium in your blood.

Hypercalcemia can affect anyone at any age, but it’s most common in people assigned female at birth over age 50 (after menopause). In most cases, this is due to an overactive parathyroid gland.

Hypercalcemia affects approximately 1% to 2% of the general population. Most of the cases — about 90% — are due to primary hyperparathyroidism and cancer-related hypercalcemia (hypercalcemia of malignancy).

Most cases of hypercalcemia aren’t life-threatening and many people don’t have any symptoms. Healthcare providers often catch it early from routine blood tests.

Symptoms of high calcium levels can include:

- Abdominal pains

- Bone pain

- Constipation

- Forgetfulness, depression or irritability

- Headaches

- Low appetite

- More frequent urination and thirst

- Muscle aches, weakness, cramping and/or twitches.

- Nausea and vomiting

- Tiredness/Fatigue

If you have hypercalcemia, your doctor will aim to identify and treat the condition that’s causing high calcium levels.

Diseases or conditions that can cause hypercalcemia can include:

- Abnormal heart rhythm (= arrhythmia).

- Adrenal gland failure

- Being bedridden or immobilized for a prolonged period of time

- Breast cancer

- Certain cancers of the blood

- Coma

- Confusion

- Hyperparathyroidism

- Hyperthyroidism (an overactive thyroid gland)

- Kidney failure

- Lung cancer

- Lung diseases such as sarcoidosis and tuberculosis

- Medications such as lithium and thiazide diuretics

- Multiple myeloma

- Paget’s disease of the bone

- Taking too much calcium or vitamin D through supplementation

- Taking too much calcium carbonate (Tums or Rolaids) supplements

If your calcium blood test results reveal that you have high or low levels of calcium, it doesn't necessarily mean that you have a medical condition. Other factors, such as diet and certain medications, can affect your calcium levels. There could’ve also been an error in the collection, transport or processing of the test.

Potential treatment of hypercalcemia:

Treatment of hypercalcemia depends on what’s causing it and how severe it is. In mild cases of hypercalcemia, your healthcare provider may tell you to:

- Drink more water.

- Switch to a non-thiazide diuretic or blood pressure medication.

- Stop taking or lower your dose of calcium-rich antacid tablets.

- Stop taking or lower your dose of calcium supplements and calcium-containing supplements, such as multivitamins.

If the hypercalcemia is due to an overactive parathyroid gland, your provider will most likely recommend surgery to have the overactive parathyroid gland(s) removed.

If the hypercalcemia is severe, and/or causing significant symptoms, your provider may recommend immediate hospitalization for IV fluids and other treatments.

Potential prevention of hypercalcemia:

Not all cases of hypercalcemia can be prevented, but avoiding excess intake of calcium pills and calcium-based antacid tablets can help.

Be sure to talk with your healthcare provider if you have a family history of high calcium, kidney stones or parathyroid conditions. Avoid taking dietary supplements, vitamins or minerals without first discussing them with your provider.

Prognosis of hypercalcemia:

Prognosis, like treatment, depends on the cause and severity of hypercalcemia. When hypercalcemia happens due to a benign (= not harmful) condition or temporary situation, it generally has a good prognosis.

People who have hypercalcemia due to cancer often experience symptoms and require frequent hospitalizations.

Complications of hypercalcemia?

Complications of long-term hypercalcemia are rare since calcium levels are checked in routine blood panels and healthcare providers usually catch hypercalcemia early, but complications can include:

- Calcium deposits in your kidney (nephrocalcinosis) that cause poor kidney function.

- Kidney failure

- Kidney stones

- High blood pressure (hypertension)

- Depression

- Bone cysts

- Bone fractures

- Osteoporosis