Calcium

The Calcium test measures the level of calcium in the blood. Calcium is a vital mineral essential for bone health, muscle function, nerve transmission, and hormone secretion. The test helps evaluate bone disorders, kidney function, and parathyroid gland activity.

1. What Is Calcium?

• Calcium is the most abundant mineral in the body, with over 99% stored in bones and teeth.

• The remaining calcium circulates in the blood and is tightly regulated by the parathyroid hormone (PTH), vitamin D, and calcitonin.

• Blood calcium exists in two forms:

  - Bound calcium: Attached to proteins (like albumin).

  - Free (ionized) calcium: The biologically active form.

2. Why Is the Calcium Test Performed?

This test is used to:

• Evaluate bone health and screen for osteoporosis or calcium imbalances.

• Monitor kidney function and chronic kidney disease (CKD).

• Diagnose parathyroid gland disorders (e.g., hyperparathyroidism).

• Assess symptoms such as muscle cramps, tingling, or confusion.

3. Calcium Reference Ranges

• Total Calcium (serum): 8.5 – 10.5 mg/dL

• Ionized Calcium: 4.4 – 5.4 mg/dL

• These ranges may vary slightly by lab. Total calcium can be influenced by albumin levels.

4. How to Interpret Calcium Results

🔹 Elevated Calcium (Hypercalcemia):

• May indicate hyperparathyroidism, certain cancers, excessive vitamin D intake, or dehydration.

• Symptoms include fatigue, nausea, constipation, kidney stones, and confusion.

🔹 Low Calcium (Hypocalcemia):

• May result from hypoparathyroidism, kidney disease, vitamin D deficiency, or magnesium imbalance.

• Symptoms include muscle cramps, tingling, seizures, or heart rhythm problems.

5. What Can Affect Calcium Levels?

• Parathyroid gland disorders

• Vitamin D levels

• Kidney function

• Certain cancers (e.g., bone metastases)

• Medications (e.g., diuretics, lithium, calcium supplements)

6. How Is the Test Performed?

• A blood sample is drawn, usually with no special preparation required for total calcium.

• Ionized calcium may require fasting and special handling.

7. When to See a Doctor

🚨 Contact your healthcare provider if you:

• Have symptoms of calcium imbalance (e.g., cramps, fatigue, mental confusion).

• Are being treated for kidney disease, thyroid/parathyroid disorders, or certain cancers.

• Have abnormal calcium test results or are at risk for osteoporosis.

🔹 Key Takeaways

✅ Calcium is essential for bone strength, muscle function, and nerve signaling.

✅ Abnormal levels may indicate endocrine, kidney, or nutritional disorders.

✅ Both total and ionized calcium may be tested depending on clinical needs.