Patient Guide to Understanding Your Medical Diagnostic Test and Its Purpose
A blood test that measures the amount of calcium in your blood to evaluate bone health, nerve function, and muscle contraction.
{"Measures calcium levels in your blood serum","Helps diagnose bone disorders, parathyroid problems, and nerve issues","Simple blood draw test with no special fasting required"}
Key facts at a glance
- LOINC
- 9467-2
- Short code
- CA
- Synonyms
- Calcium Wat-mCnc
- Category
- electrolyte
- Sample
- serum
- Container
- SST (Serum separator tube) or red top tube
- Units
- not specified
- Ref low
- 8.5
- Ref high
- 10.5
- Critical range
- 7 not specified – 13 not specified
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Atomic absorption spectrophotometry (AAS) or Colorimetric method ( Arsenazo III )
- CPT
- 82310
- SNOMED
- 271071001
- Specimen volume
- 1 mL serum minimum
- Stability
- Room temperature: 7 days; Refrigerated (2-8°C): 14 days; Frozen (-20°C): 3 months
- Hemolysis max
- 50
- Lipemia max
- 300
- Icterus max
- 20
- TAT
- 1–24 hours
- Order
- routine
What is this medical test used to check, and why might your provider recommend it?
The serum calcium test measures the amount of calcium in the liquid part of your blood (serum). Calcium is a vital mineral that plays a key role in building strong bones and teeth, helping muscles contract, enabling nerves to send signals, and supporting blood clotting. Your body carefully regulates calcium levels through hormones like parathyroid hormone (PTH) and vitamin D.
How is the test performed, and what can you expect during the procedure?
A healthcare professional will draw a small sample of blood from a vein in your arm using a needle. The blood sample is then sent to a laboratory for analysis. The procedure usually takes just a few minutes and is generally well-tolerated.
Reference range
Not applicable (environmental/water sample; typical drinking water 10-100 mg/L)not specified
No patient preparation required; collect representative water sample in clean container
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The serum calcium test is used to screen for, diagnose, and monitor conditions affecting calcium levels in the blood. High calcium levels (hypercalcemia) may indicate hyperparathyroidism, certain cancers, excessive vitamin D intake, or kidney problems. Low calcium levels (hypocalcemia) may suggest hypoparathyroidism, vitamin D deficiency, kidney disease, or pancreatitis. The test is also used to monitor patients on calcium supplements or those with known bone or parathyroid disorders.
Frequently asked questions
Do I need to fast before this test?
What are normal calcium levels?
What does it mean if my calcium is high?
What does it mean if my calcium is low?
Sources
- 1
- 2
- 3NIH - Calcium in SerumSource
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 10, 2026. · Read our editorial policy