Calcium in Serum or Plasma (Mass Concentration)
This test measures the amount of calcium, a mineral essential for many body functions, including muscle and nerve activity, blood clotting, and bone health.
["Your calcium level helps doctors assess bone health, muscle function, and overall mineral balance in your body."]
Key facts at a glance
- LOINC
- 1992-7
- Short code
- CALC
- Synonyms
- Calcit SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube; plasma acceptable in EDTA or heparin tubes
- Units
- N/A
- Ref low
- 0
- Ref high
- 8
- Critical range
- — – 100 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunoassay (Chemiluminescent)
- CPT
- 82308
- SNOMED
- 1005733001
- Specimen volume
- 1.0 mL (minimum 0.5 mL)
- Stability
- Room temperature: 4 hours; Refrigerated (2-8°C): 24 hours; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- 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 cause symptoms such as muscle cramps, weakness, or abnormal heart rhythms. It’s also used to monitor conditions like osteoporosis, kidney disease, or hyperparathyroidism.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it involves drawing blood. If you’re on certain medications (like calcium supplements or diuretics), let your healthcare provider know.
What Happens During the Test?
A healthcare professional will draw blood from a vein in your arm. The blood sample is then sent to a lab for analysis using an automated method to measure calcium levels accurately.
What Are the Results Mean?
Results are compared to standard reference ranges, but your doctor will interpret them based on your overall health and symptoms. Very high or low levels may trigger further testing or treatment.
Reference range
Male: <8.0 pg/mL; Female: <5.0 pg/mL (values vary by assay method and laboratory)N/A
No fasting required. Patient should be well-hydrated. Recent administration of radioisotopes may interfere with some assay methods.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal calcium levels can indicate underlying health issues, such as bone disorders, kidney problems, or hormonal imbalances. Low calcium (hypocalcemia) may lead to muscle spasms or fatigue, while high calcium (hypercalcemia) could cause nausea, confusion, or kidney stones. Regular monitoring helps manage these conditions effectively.
Short name
Calcium Level
Frequently asked questions
What causes abnormal calcium levels?
How long does it take to get results?
Can I eat or drink before the test?
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