Calcium in Serum (Total)
This test measures the amount of calcium, a mineral essential for bone health, muscle function, and nerve signaling, in your blood serum.
["Your blood calcium levels help ensure proper bone strength and vital bodily processes."]
Key facts at a glance
- LOINC
- 16510-0
- Short code
- CALC8
- Synonyms
- Calcit sp8 p chal SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum tube or serum separator tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–99 years
- Method
- Immunoassay (Chemiluminescent or Radioimmunoassay)
- CPT
- 82308
- SNOMED
- 39520004
- Specimen volume
- 1-2 mL of serum
- Stability
- Serum stable for 8 hours at room temperature, 24 hours at 2-8°C, and up to 3 months at -20°C or colder
- Hemolysis max
- 100
- Lipemia max
- 500
- Icterus max
- 25
- 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 affect heart rhythm, muscle function, or bone health. It’s often done when symptoms such as muscle cramps, fatigue, or abnormal heartbeats are present.
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’s part of a broader metabolic panel, but this depends on your doctor’s instructions.
What the Results Mean
Results are typically reported in milligrams per deciliter (mg/dL). While exact ranges vary by lab, low levels may indicate conditions like hypoparathyroidism, while high levels could suggest kidney disease or overuse of certain medications.
Common Conditions Linked to Abnormal Results
Low calcium levels (hypocalcemia) may cause muscle spasms, numbness, or irregular heartbeats. High calcium levels (hypercalcemia) can lead to fatigue, nausea, or kidney stones.
Reference range
Reference ranges for post-stimulation calcitonin vary by laboratory and assay methodology; results should be interpreted in conjunction with the stimulation test protocol and clinical context.N/A
No special preparation required. Patient should be informed about the stimulation challenge procedure (e.g., calcium or pentagastrin infusion) and the 8th specimen collection timing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Total Serum Calcium
Frequently asked questions
What causes my calcium test results to be different from what I’ve heard in the news or online?
Can I eat or drink anything before this test?
Will I feel any pain or discomfort during the blood draw?
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