Test Overview

The Calcium Blood Test measures the level of calcium in the blood. Calcium is essential for strong bones and teeth, muscle function, nerve signaling, and blood clotting. Abnormal levels may indicate underlying health conditions such as kidney disease, bone disorders, or parathyroid gland dysfunction.

Test Types

Total Calcium Test – Measures both bound and free calcium in the blood.
Ionized Calcium Test – Measures only free calcium (biologically active form).
Urine Calcium Test – Evaluates calcium excretion in urine, used for kidney stone risk assessment.

Calcium Test Results & Ranges

Test Component:	Normal Range:	Abnormal Range:
Total Calcium	8.5–10.5 mg/dL	<8.5 mg/dL (low) or >10.5 mg/dL (high)
Ionized Calcium	4.6–5.3 mg/dL	<4.6 mg/dL (low) or >5.3 mg/dL (high)
Urine Calcium	100–300 mg/day	<100 mg/day (low) or >300 mg/day (high)

Possible Causes of Abnormal Calcium Levels

Low Calcium (Hypocalcemia)

Vitamin D deficiency
Hypoparathyroidism (low parathyroid hormone)
Chronic kidney disease
Magnesium deficiency
Certain medications (e.g., diuretics, bisphosphonates)

High Calcium (Hypercalcemia)

Overactive parathyroid glands (hyperparathyroidism)
Excessive vitamin D or calcium intake
Certain cancers (lung, breast, multiple myeloma)
Kidney disease
Prolonged immobilization

Symptoms of Calcium Imbalance

Low Calcium Symptoms

Muscle cramps or spasms
Numbness or tingling (especially in fingers or around the mouth)
Fatigue or confusion
Brittle nails and dry skin

High Calcium Symptoms

Frequent urination and excessive thirst
Nausea, vomiting, or constipation
Weakness or fatigue
Confusion or difficulty concentrating

Sample Collection

Sample Type: Blood sample (drawn from a vein) or 24-hour urine collection
Fasting Required: No, unless specified by the doctor
Turnaround Time: 24–48 hours

Why Get a Calcium Test?

Evaluates bone health and risk of osteoporosis
Detects kidney and parathyroid disorders
Monitors calcium levels in those with chronic conditions

Calcium