Calcium in Serum (Mass Concentration)
This test measures the amount of calcium present in your blood serum, which is important for maintaining healthy bones, muscles, and nerve function.
["Your blood calcium levels help ensure proper muscle contractions, nerve signaling, and bone health."]
Key facts at a glance
- LOINC
- 56511-9
- Short code
- CALC2MIN
- Synonyms
- Calcit 2M p chal SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube without anticoagulant for serum; plasma may be collected in EDTA or heparinized tubes depending on laboratory protocol
- Units
- N/A
- 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
- 39539002
- Specimen volume
- 1-2 mL of serum or plasma per time point; for multiple time-point collections, additional volume may be required
- Stability
- Serum/plasma stable for 4 hours at room temperature (20-25°C); refrigerated (2-8°C) for up to 24 hours; frozen at -20°C or lower for up to 30 days for batched testing. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 150
- Icterus max
- 20
- TAT
- 24–72 hours
- Order
- routine
This test is done to help your doctor check how well a specific part of your body is working and to look for early signs of illness. Your care team may order it as part of a routine checkup, to help find the cause of symptoms you are having, or to monitor a condition you already know you have.
Doctors may order this test to check for conditions like low or high calcium levels, which can cause symptoms such as muscle spasms, fatigue, or irregular heart rhythms. It may also be used to monitor conditions like kidney disease, osteoporosis, or hormonal imbalances that affect calcium metabolism.
Your results are compared with a normal reference range, and values that fall outside that range may point to a condition that needs a closer look. A single number rarely tells the whole story, so your doctor will consider your symptoms, medical history, and other test results before explaining what your result means for you.
Results are not provided with specific numeric ranges here, as they can vary by lab and medical context. Your healthcare provider will interpret the result in relation to your overall health and symptoms.
Waiting for results can feel stressful, and many people feel anxious during that time. If your results come back normal, you may feel relieved; if something looks unusual, you may feel worried or confused. Whatever the outcome, your care team is there to explain the findings clearly, put them in context, and answer any questions you have.
You may not experience any symptoms if your calcium levels are within a typical range. However, if levels are abnormal, you might feel tired, weak, or have unusual bone or muscle pain.
The test is usually done in a clinic, hospital, or laboratory by a trained member of your care team. Depending on the type of test, a small sample of blood may be drawn from a vein in your arm, or another sample may be collected. The procedure is typically quick, causes only minor discomfort if any, and you can usually go home right afterward.
A blood sample is drawn from a vein, usually in your arm. The blood is then sent to a lab for analysis to determine the calcium concentration.
Reference range
Reference ranges for calcitonin stimulation testing vary by laboratory, basal levels, sex, and type of provocative agent (calcium or pentagastrin). Peak calcitonin levels at 2 minutes post-challenge are interpreted in conjunction with basal values; fold-rise from baseline is clinically significant for diagnosis of medullary thyroid carcinoma (MTC) and C-cell hyperplasia.N/A
Fasting is not required for this test. Patients should be informed that a provocative agent (calcium gluconate infusion or pentagastrin injection) will be administered prior to specimen collection. Patient should remain supine during the test. Discuss any medications, recent radioisotope studies, or known allergies with the ordering physician prior to testing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Calcium Levels and Health
Short name
Serum Calcium Level
Frequently asked questions
Calcium is vital for many bodily functions, including muscle and nerve function, blood clotting, and maintaining strong bones. Abnormal levels can indicate underlying health issues like kidney disease, thyroid disorders, or vitamin D deficiencies.
The frequency depends on your health condition and medical needs. Your doctor will determine how often you need this test based on your symptoms, medical history, and other tests.
What are the common symptoms of low or high calcium?
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