Serum Calcium (Total)
This test measures the amount of calcium present in your blood serum. Calcium is an essential mineral that plays a key role in maintaining strong bones, healthy teeth, and proper muscle and nerve function.
["Check your blood calcium levels to help diagnose conditions like low or high calcium, which can affect bones, muscles, or heart function."]
Key facts at a glance
- LOINC
- 39048-4
- Short code
- XR Scapula AP
- Synonyms
- XR Scapula AP
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- xr
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Doctors may order a total serum calcium test to investigate symptoms such as muscle cramps, bone pain, frequent fractures, or unusual fatigue. It can also be used to monitor conditions like kidney disease, certain cancers, or hormonal imbalances that affect calcium levels.
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 isn’t always required for just the calcium test alone.
How the Test Is Done
A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but the procedure is quick and typically doesn’t cause lasting discomfort.
Possible Results and Interpretation
Results are compared to standard reference ranges, but your doctor will interpret them in the context of your overall health and symptoms. Very low or very high calcium levels can signal underlying health concerns.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Total Serum Calcium
Frequently asked questions
Low serum calcium (hypocalcemia) may cause muscle spasms, numbness, or an irregular heartbeat, while high serum calcium (hypercalcemia) can lead to fatigue, kidney stones, or confusion. Both conditions require medical evaluation to determine the cause and appropriate treatment.
A normal calcium level doesn’t necessarily mean you’re healthy. It simply indicates that your calcium is within the typical range for the general population. Your doctor will assess your results alongside your medical history, symptoms, and other test results to determine if further action is needed.
Dietary factors like calcium-rich foods or supplements can influence blood calcium levels, but a single test result may not reflect your current dietary intake. If your doctor suspects dietary factors are affecting your results, they may recommend additional testing or monitoring.
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