Serum Calcium (Mass Concentration)
This test measures the amount of calcium in your blood serum. Calcium is an essential mineral that helps with muscle and nerve function, bone health, and blood clotting.
["Your blood calcium levels help doctors assess bone health and other health conditions."]
Key facts at a glance
- LOINC
- 50469-6
- Short code
- CALC1
- Synonyms
- Calcit sp1 SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube; plasma may be collected in EDTA or heparin tubes.
- Units
- N/A
- Ref low
- 0
- Ref high
- 8.4
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunoassay (Chemiluminescent/ELISA)
- CPT
- 82308
- SNOMED
- 103140009
- Specimen volume
- 1-2 mL of serum or plasma
- Stability
- Stable for 24 hours at room temperature; 7 days at 2-8°C (refrigerated); up to 3 months at -20°C (frozen). Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 300
- Icterus max
- 50
- 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 affect bones, muscles, nerves, or heart function. It may also be done if you have symptoms like muscle spasms, confusion, or frequent bone fractures.
What to Expect Before the Test
No special preparation is needed for this test. You may have a small needle inserted into your arm to draw blood. The process is quick and usually painless. If you’re on blood thinners or have a history of bleeding issues, let your doctor know beforehand.
What the Results Mean
Results are typically reported in milligrams per deciliter (mg/dL). While reference ranges vary slightly by lab, normal levels are usually between 8.4 and 10.2 mg/dL. Abnormal results may indicate conditions like hypocalcemia (low calcium) or hypercalcemia (high calcium), which can cause various symptoms.
Common Conditions Linked to Calcium Levels
Low calcium levels (hypocalcemia) may be linked to conditions like vitamin D deficiency, kidney disease, or certain medications. High calcium levels (hypercalcemia) can result from overactive thyroid, cancer, or prolonged bed rest. Both conditions can affect your bones, heart, and other organs.
Reference range
Reference ranges vary by assay method and laboratory. Typical adult reference ranges: Males <8.4 pg/mL; Females <5.0 pg/mL. Pediatric and neonatal ranges differ.N/A
No special preparation required. Some clinicians recommend fasting overnight to minimize dietary influences, though not strictly required. Patient should be informed that the test may be part of a stimulation protocol (e.g., pentagastrin or calcium stimulation test).
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Calcium Level
Frequently asked questions
What causes my calcium test results to be different from what I expected?
Will I need to do anything special if my calcium levels are out of range?
Can diet or supplements affect my 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