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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 bone strength and nerve function."]

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

Key facts at a glance

LOINC
36024-8
Short code
XR tomo Humerus
Synonyms
XR tomo Humerus
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-tomography
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 check for conditions like low or high calcium levels, which can affect your bones, heart, or muscles. It might also be done if you have symptoms such as muscle spasms, confusion, or abnormal heart rhythms.

What to Expect Before the Test

No special preparation is needed for this test. You may have a small needle inserted into your arm or vein to draw a blood sample. It usually takes a few minutes.

What the Results Mean

While specific reference ranges can vary by lab, low calcium levels may indicate conditions like vitamin D deficiency or kidney problems, while high levels could suggest overuse of certain medications or conditions like hyperparathyroidism.

Common Conditions Affecting Results

Abnormal calcium levels can be linked to various health issues, such as osteoporosis, kidney disease, or certain hormonal imbalances. Your doctor will review your results in the context of your overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Your doctor may use these results to diagnose or monitor conditions affecting calcium metabolism, such as hypocalcemia (low calcium) or hypercalcemia (high calcium).

Short name

Total Serum Calcium

Frequently asked questions

What causes my calcium levels to be abnormal?
Abnormal calcium levels can result from dietary factors, certain medications, kidney issues, hormonal imbalances, or underlying health conditions like cancer or thyroid disorders.
How often should I get this test?
Your doctor will determine the frequency based on your health needs, symptoms, and any ongoing conditions. Regular monitoring might be recommended if you have chronic health issues.
Can diet affect my calcium test results?
Yes, your diet can influence calcium levels. High intake of calcium-rich foods or supplements may temporarily raise your calcium levels, so it’s best to avoid large changes in diet before testing.
  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