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.
["Blood calcium levels help diagnose conditions like low or high calcium, which can affect your bones, heart, and other organs."]
Key facts at a glance
- LOINC
- 58891-3
- Short code
- CALC1MIN
- Synonyms
- Calcit 1M p chal SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum tube (no anticoagulant) or serum separator tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 10
- Critical range
- — – 1000 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Chemiluminescent Immunoassay (CLIA) / Immunochemiluminometric Assay (ICMA)
- CPT
- 82308
- SNOMED
- 39500004
- Specimen volume
- 1.0 mL serum minimum; 2.0 mL preferred
- Stability
- Serum stable for 2 hours at room temperature; refrigerated (2-8°C) for up to 24 hours; frozen at -20°C or below for up to 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
Why It’s Done
Your healthcare provider may order this test if you have symptoms like muscle spasms, confusion, or unusual fatigue. It’s also used to monitor conditions like kidney disease, bone disorders, or certain cancers that can affect calcium levels.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it involves a blood draw, but this depends on your provider’s instructions.
How the Test Works
A small sample of blood is taken from a vein in your arm. The sample is then analyzed to measure calcium concentration using a specialized laboratory method.
Possible Results and Their Meaning
Results are compared to standard ranges for healthy adults. Low calcium can cause weakness or numbness, while high levels may lead to kidney stones or heart issues. Your provider will discuss your specific results with you.
Reference range
Post-challenge calcitonin levels vary by stimulation agent (calcium or pentagastrin). Peak stimulated values are interpreted relative to baseline. Basal reference range typically <10 pg/mL (males) and <5 pg/mL (females) for adults. Post-stimulation rise is considered significant if >100 pg/mL (males) or >50 pg/mL (females), suggestive of medullary thyroid carcinoma (MTC). Consult laboratory-specific reference ranges for interpretation.N/A
No fasting required. Patient should remain supine for at least 15-30 minutes prior to specimen collection to avoid postural variation. Pentagastrin may cause transient nausea, flushing, chest tightness, and abdominal cramping. Calcium infusion may cause flushing, warmth, or nausea. Inform patient of potential side effects of stimulation agent.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Calcium Level
Frequently asked questions
What might cause abnormal 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 16, 2026. · Read our editorial policy