Calcium, Serum or Plasma, Substance Concentration (Mass Concentration)
This test measures the amount of calcium in your blood, which is important for many body functions, including muscle and nerve activity.
["Calcium helps your body stay strong and supports normal heart rhythm and blood clotting."]
Key facts at a glance
- LOINC
- 77667-4
- Short code
- CALCT-2PC
- Synonyms
- Calcit 2M p chal SerPl-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST, tiger-top) or plain red-top tube for serum; lithium heparin or EDTA plasma tubes are acceptable alternatives.
- Units
- N/A
- Ref low
- 0
- Ref high
- 11.8
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–99 years
- Method
- Chemiluminescent Immunoassay (CLIA) or Electrochemiluminescence Immunoassay (ECLIA)
- CPT
- 82308
- SNOMED
- 39503006
- Specimen volume
- 1-2 mL of serum or plasma (minimum 0.5 mL)
- Stability
- Serum/plasma stable for 8 hours at room temperature; 24 hours refrigerated at 2-8°C; for longer storage, freeze at -20°C or below for up to 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 50
- Lipemia max
- 100
- Icterus max
- 25
- TAT
- 24–72 hours
- Order
- routine
Why It’s Done
Your doctor may order this test to check for conditions like low or high calcium levels, which can affect bones, muscles, nerves, or heart. It’s also used to diagnose or monitor conditions such as kidney disease, vitamin D deficiency, or certain cancers.
What to Expect
A blood sample is taken from a vein, usually in your arm. You may feel a slight pinch, but it shouldn’t cause discomfort. The test is quick and doesn’t require special preparation.
Normal vs. Abnormal Results
Results don’t include specific reference ranges. Your doctor will compare your result to your individual health needs and any known conditions.
Common Conditions Affecting Results
Low calcium (hypocalcemia) may cause muscle spasms, numbness, or irregular heartbeat. High calcium (hypercalcemia) could lead to fatigue, nausea, or kidney problems. Both can be linked to underlying health issues.
Reference range
Reference values vary by laboratory; basal calcitonin in adult males typically <11.8 pg/mL and in adult females typically <4.8 pg/mL. Post-stimulation calcitonin values depend on the provocative agent (e.g., calcium or pentagastrin) and clinical context. A peak post-stimulation calcitonin >100 pg/mL is highly suggestive of medullary thyroid carcinoma (MTC).N/A
Fasting is not required. However, patients should be informed that the test involves a specific provocative stimulation protocol (calcium or pentagastrin infusion). No special dietary restrictions are generally needed prior to the baseline draw, but caffeine intake should be avoided prior to testing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal calcium levels can signal serious health issues, such as metabolic bone disease, thyroid disorders, or kidney problems. Regular monitoring helps manage these conditions and prevent complications.
Short name
Calcium Level
Frequently asked questions
How long does it take to get my results?
What should I do if my calcium level is out of range?
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