Calcium, Serum or Plasma (Mass Concentration)
Your blood test measures the amount of calcium, a mineral essential for muscle and nerve function, bone health, and blood clotting.
["Calcium helps your body stay strong, function properly, and maintain healthy cells and tissues."]
Key facts at a glance
- LOINC
- 21643-2
- Short code
- CACNA1S R1239H
- Synonyms
- CACNA1S p.R1239h Bld/T Ql
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA tube (purple-top) for whole blood; sterile container for tissue specimens
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- molgen
- CPT
- 81403
- SNOMED
- 5304004
- Specimen volume
- 3-5 mL whole blood; minimum 1 mL for pediatric samples; 5-10 mg tissue
- Stability
- Whole blood: Stable for 7 days at room temperature (20-25°C) or 30 days refrigerated (2-8°C); avoid freezing for EDTA whole blood. Tissue: Stable for 24 hours refrigerated; frozen tissue stable for long-term storage at -20°C or -80°C. DNA extracted from specimen stable for years at -20°C.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 168–720 hours
- Order
- routine
Why This Test Is 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 irregular heartbeat. It may also be used to monitor bone health, kidney function, or thyroid issues.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into your arm or vein to draw blood. If you’re having a urine test for calcium, you might be asked to collect a sample over 24 hours.
What the Test Results Mean
Results are interpreted by your healthcare provider based on your overall health and symptoms. Abnormal levels can signal underlying health concerns that need further evaluation.
Common Conditions Affecting Calcium Levels
Low calcium (hypocalcemia) may be linked to conditions like vitamin D deficiency, kidney problems, or certain medications. High calcium (hypercalcemia) could result from overactive thyroid, bone diseases, or prolonged exposure to sunlight.
Reference range
Negative (absence of CACNA1S p.Arg1239His mutation); Wild-type allele detected. Reference result indicates the Arg1239His variant is NOT present in the analyzed specimen.N/A
No special patient preparation required. Patient should be informed that genetic testing results may have implications for family members. Pre-test genetic counseling is recommended. Patients should provide informed consent prior to genetic testing as per institutional policy.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Calcium Level
Frequently asked questions
How long does it take to get my calcium test results?
Can diet affect my calcium test results?
What should I do if my calcium test is abnormal?
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