Serum or plasma concentration of calcium (total)
This test measures the amount of calcium in your blood, which is important for keeping your bones strong, muscles working properly, and nerves functioning correctly.
["A calcium level helps doctors check for bone health, heart rhythm issues, or other health problems."]
Key facts at a glance
- LOINC
- 26134-7
- Short code
- XR Acetabulum-L Views
- Synonyms
- XR Acetabulum-L Views
- 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 Is This Test Done?
Your doctor may order this test to diagnose or monitor conditions like low or high calcium levels, kidney disease, bone disorders, or metabolic issues. It can also help evaluate symptoms such as muscle cramps, confusion, or abnormal heart rhythms.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for a few hours before the test if it’s part of a broader metabolic panel. Bring any recent lab results or medications you’re taking to your appointment.
What Happens During the Test?
A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood sample is then sent to a lab for analysis.
What Are Possible Results?
Results are reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). While reference ranges vary by lab, lower or higher levels than expected may 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 calcium levels (hypocalcemia) can cause muscle spasms, numbness, or irregular heartbeats, while high levels (hypercalcemia) may lead to fatigue, nausea, or kidney stones. Both conditions can stem from conditions like vitamin D deficiency, kidney disease, or certain cancers.
A normal calcium level doesn’t always mean you’re healthy. Your doctor may still recommend follow-up tests or treatments if they suspect an underlying issue, such as bone disease or hormonal imbalances.
Yes, your diet can influence calcium levels. High intake of calcium-rich foods (like dairy or leafy greens) or certain medications (like calcium supplements) may affect results. Avoiding these for a few days before testing can help ensure accurate results.
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