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Calcium, Serum/Plasma, Mass Concentration

Published: August 9, 2026Updated: August 15, 2026

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.

Quick summary

Your calcium levels help ensure strong bones and proper heart and nerve function.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
16505-0
Short code
CALC10PC
Synonyms
Calcit 10M p chal SerPl-mCnc
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) or red-top vacutainer tube
Units
N/A
Ref low
0
Ref high
10
Critical range
— – 1000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–99 years
Method
Chemiluminescent Immunoassay (CLIA) or Electrochemiluminescence Immunoassay (ECLIA)
CPT
82308
SNOMED
39579002
Specimen volume
1.0 mL serum (minimum 0.5 mL)
Stability
Serum calcitonin is stable for 2 hours at room temperature, 24 hours at 2-8°C, and up to 6 months frozen at -20°C. Avoid repeated freeze-thaw cycles.
Hemolysis max
50
Lipemia max
100
Icterus max
20
TAT
24–72 hours
Order
routine

Why Is This Test Done?

Your doctor may order this test to check for conditions like low or high calcium levels, which can cause symptoms such as muscle cramps, confusion, or irregular heartbeat. It may also be done to monitor conditions like kidney disease, bone disorders, or certain medications that affect calcium.

What to Expect Before the Test

No special preparation is needed for this test. You may have a small needle inserted into your arm or vein to draw blood. If you’re nervous, let your healthcare provider know so they can help you relax.

What the Results Mean

Results are compared to a standard range, but exact values can vary by lab. Low calcium can lead to weakness or numbness, while very high levels might cause nausea or rapid heart rate. Your doctor will discuss your specific results with you.

Common Conditions This Test Helps Diagnose

This test helps identify issues like hypocalcemia (low calcium), hypercalcemia (high calcium), or conditions affecting bone metabolism, such as osteoporosis or kidney problems.

Reference range

Reference ranges for stimulated calcitonin vary by challenge agent (calcium, pentagastrin) and laboratory method. Baseline calcitonin typically <10 pg/mL (males) and <5 pg/mL (females) in adults. Peak stimulated values should be interpreted in conjunction with baseline and clinical context; a peak >100 pg/mL is suggestive of medullary thyroid carcinoma (MTC).N/A

Specimen: serum

No special fasting required. Patient should be in a rested state prior to testing. Inform the laboratory of any medications, particularly proton pump inhibitors or calcium supplements, which may influence calcitonin secretion.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal calcium levels can signal underlying health issues like thyroid disorders, vitamin D deficiency, or certain cancers. Your doctor will use these results alongside other tests and symptoms to guide treatment.

Short name

Calcium Level

Frequently asked questions

How often will I need this test?
The frequency depends on your health condition. Some people need it yearly, while others may require it more often if they have ongoing medical issues like kidney disease or bone disorders.
What can affect my calcium test results?
Certain foods (like dairy or calcium supplements), medications (such as antacids or some heart medications), and health conditions (like kidney disease) can influence results. Always tell your doctor about all medications or supplements you take.
Do I need to fast before this test?
No fasting is required for this blood test, but you may be asked to avoid certain foods or drinks (like caffeine) for a short time if your doctor specifies.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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