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Serum Calcium (Total)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of calcium in your blood serum, which is important for maintaining healthy bones, muscles, and nerves.

Quick summary

["Your blood calcium levels help support strong bones and proper nerve and muscle function."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
37655-8
Short code
XR Scapula 2V
Synonyms
XR Scapula 2V
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 Might Be Ordered

Your doctor may order this test if you have symptoms like muscle cramps, bone pain, or unusual fatigue. It could also be done to check for conditions like osteoporosis, kidney disease, or certain hormonal imbalances.

What to Expect Before the Test

You can eat and drink normally before this test. No special preparation is needed, but let your doctor know about any medications you’re taking, as some may affect results.

How the Test Is Performed

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed for calcium levels.

Possible Results and Their Meaning

Results are compared to standard ranges, but exact values can vary by lab. Low calcium may cause weakness or numbness, while very high levels might lead to kidney stones or heart issues.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum Calcium

Frequently asked questions

What does a low or high calcium level mean?
Low calcium (hypocalcemia) can cause muscle spasms, tingling in hands/feet, or irregular heartbeat. High calcium (hypercalcemia) may lead to fatigue, nausea, or kidney problems. Both conditions can stem from underlying health issues like thyroid disorders, kidney disease, or bone diseases.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status, symptoms, or risk factors. Regular monitoring may be recommended if you have conditions like osteoporosis, kidney disease, or are taking calcium-regulating medications.
Can diet affect calcium test results?
Yes, dietary calcium intake can influence results. Avoiding large amounts of calcium supplements or high-calcium foods (like dairy) for a few days before testing may help ensure more accurate results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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