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Serum or plasma concentration of calcium (total)

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

This test measures the amount of calcium in your blood, which is important for maintaining strong bones, proper muscle function, and normal nerve signaling.

Quick summary

["Your blood calcium levels help support bone health and many vital body processes."]

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

Key facts at a glance

LOINC
37635-0
Short code
XR Acetabulum 3V
Synonyms
XR Acetabulum 3V
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 recommend this test if you have symptoms like muscle cramps, numbness, or unusual fatigue. It could also be checked during routine health evaluations, especially if you have conditions like kidney disease, osteoporosis, or certain hormonal disorders.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on blood thinners or have a history of bleeding disorders, let your doctor know beforehand.

What to Expect During the Test

The blood sample is taken from a vein in your arm. You might feel a slight pinch, but it usually doesn’t cause discomfort. The test itself takes just a few minutes, and you can resume normal activities afterward.

What the Results Mean

Results are compared to standard reference ranges to identify if your calcium levels are too high or too low. Abnormal levels can signal underlying health issues that need further evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Abnormal calcium levels can indicate conditions such as hyperparathyroidism (too much calcium), hypoparathyroidism (too little calcium), kidney problems, or metabolic bone diseases. High levels may also be linked to certain cancers or medications.

Short name

Total Calcium

Frequently asked questions

How often should I get this test?
The frequency depends on your health status. Routine adults may not need it unless recommended by their doctor. People with chronic conditions like kidney disease or osteoporosis may have it checked more often.
What causes calcium levels to change?
Calcium levels can be affected by diet, vitamin D levels, kidney function, hormones (like parathyroid hormone), and certain medications. Lifestyle factors, such as calcium-rich foods or vitamin D deficiency, can also influence results.
Can diet affect this test result?
Yes, consuming large amounts of calcium-rich foods (like dairy) or supplements right before the test may temporarily alter results. Your doctor may advise timing your diet to avoid interference.
  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