Calcium, Serum or Plasma, Mass Concentration
This test measures the amount of calcium in your blood, which is important for many body functions, including muscle and nerve activity, bone health, and blood clotting.
["Your calcium levels help ensure your body stays balanced and functions properly."]
Key facts at a glance
- LOINC
- 12510-4
- Short code
- CALC6
- Synonyms
- Calcit sp6 p chal SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube (no anticoagulant). Plasma may be collected in EDTA or heparin tubes depending on assay requirements.
- Units
- N/A
- Ref low
- 0
- Ref high
- 11.5
- Critical range
- — – 1000 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunoassay (Chemiluminescent or Radioimmunoassay)
- CPT
- 82308
- SNOMED
- 313803006
- Specimen volume
- 1.0 mL serum or plasma (minimum 0.5 mL)
- Stability
- Serum/plasma stable for 8 hours at room temperature, 24 hours at 2-8°C, and up to 30 days at -20°C or colder. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 200
- Icterus max
- 40
- TAT
- 24–72 hours
- Order
- routine
Why Is This Test Done?
Doctors may order a calcium test to check for conditions like low or high calcium levels, which can cause symptoms such as muscle cramps, weakness, or irregular heartbeats. It may also be done to monitor bone health, kidney function, or certain medical treatments.
What Does the Test Involve?
A blood sample is taken from a vein, usually in your arm. The sample is then sent to a lab for analysis. The test measures the calcium concentration in your blood plasma or serum.
What Are Common Causes of Abnormal Results?
Low calcium levels (hypocalcemia) can occur due to conditions like vitamin D deficiency, kidney problems, or certain medications. High calcium levels (hypercalcemia) may result from overactive thyroid, bone diseases, or prolonged immobilization.
How Is the Test Performed?
The test is typically performed using a blood draw, where a healthcare professional inserts a needle into your arm to collect blood. The sample is then analyzed in a lab using automated equipment to measure calcium concentration.
Reference range
Basal calcitonin: Male <11.5 pg/mL, Female <4.6 pg/mL. Pentagastrin-stimulated peak values vary; stimulated calcitonin levels above 100 pg/mL in males or 50 pg/mL in females are suggestive of medullary thyroid carcinoma (MTC). Interpretation of 6th specimen post-stimulation should be compared to baseline and established reference ranges for the specific challenge protocol used.N/A
No special fasting required. Patient should be informed about the provocative stimulation procedure (e.g., pentagastrin or calcium infusion challenge). The 6th specimen is collected at a defined time point post-challenge as part of a serial sampling protocol. Avoid recent radioisotope studies that may interfere with immunometric assays.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal calcium levels can affect many body systems. Low calcium can lead to muscle spasms, numbness, and increased risk of bone fractures. High calcium can cause fatigue, nausea, and kidney stones. Regular monitoring is important for patients with conditions like osteoporosis, kidney disease, or those on long-term calcium-regulating medications.
Short name
Calcium Level
Frequently asked questions
What are the normal ranges for calcium levels?
How often should I get this test?
Can diet affect calcium test results?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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 15, 2026. · Read our editorial policy