Calcium, Serum (Total)
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 doctor may check your calcium levels to monitor bone health, detect conditions like low calcium, or assess kidney function."]
Key facts at a glance
- LOINC
- 21644-0
- Short code
- CACNA1S R528H
- Synonyms
- CACNA1S p.R528h Bld/T Ql
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (lavender-top) blood collection tube for whole blood; sterile container for tissue specimens
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- molgen
- CPT
- 81230
- SNOMED
- 5304004
- Specimen volume
- 3-5 mL whole blood in EDTA tube; 5-10 mg tissue in sterile container
- Stability
- Whole blood: Room temperature for 7 days, refrigerated (2-8°C) for 30 days, frozen (-20°C or below) for 1 year. Tissue: Refrigerated for 24 hours or frozen at -80°C for long-term storage.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 168–720 hours
- Order
- routine
Why Is This Test Done?
Doctors order this test to diagnose or monitor conditions such as hypocalcemia (low calcium), hypercalcemia (high calcium), kidney disease, or metabolic bone diseases. It may also be used during pregnancy to check for calcium-related issues or in patients with certain cancers that affect calcium metabolism.
What Does the Result Mean?
Results are not provided with specific reference ranges here. Your healthcare provider will interpret your results in relation to your overall health and medical history. Abnormally low or high levels may signal underlying health concerns that need further evaluation.
Common Reasons for Testing
This test is commonly requested if you have symptoms like muscle spasms, weakness, frequent bone fractures, or if you have a history of conditions like osteoporosis, kidney disease, or thyroid disorders.
Sample Collection and Preparation
A blood sample is drawn from a vein, usually in your arm. The blood is then separated into serum (the liquid part without clotting factors) for testing. No special preparation is needed, but fasting may be advised depending on your specific situation.
Reference range
Negative (no p.Arg528His mutation detected). Positive indicates presence of the R528H variant in the CACNA1S gene, associated with Malignant Hyperthermia susceptibility.N/A
No fasting required. Patients should provide informed consent for genetic testing. Genetic counseling is recommended prior to and following testing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Total Serum Calcium
Frequently asked questions
Low calcium levels can cause muscle cramps, numbness, or irregular heartbeats. High calcium levels may lead to nausea, confusion, or kidney stones. Regular monitoring is important for patients with chronic conditions affecting calcium balance.
What happens if my calcium level is out of range?
How often should I get this 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