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Serum/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 bone health, muscle function, and nerve signaling.

Quick summary

["Your blood calcium levels help maintain strong bones and proper heart and muscle function."]

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

Key facts at a glance

LOINC
32938-3
Short code
FH-NPg Angle Skull CT
Synonyms
FH-NPg Angle Skull CT
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct-measured
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?

Doctors may order a total calcium test to check for conditions like low or high calcium levels, which can cause symptoms such as muscle cramps, weakness, or irregular heartbeat. It’s also used to diagnose or monitor conditions like osteoporosis, kidney disease, or certain cancers.

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 blood. If you’re on blood thinners, let your healthcare provider know before the test.

What the Results Mean

Results are typically reported in milligrams per deciliter (mg/dL). Abnormal levels can indicate underlying health issues, so discuss any results with your doctor.

Common Conditions Monitored

This test helps diagnose or manage conditions such as hypocalcemia (low calcium), hypercalcemia (high calcium), and metabolic bone diseases.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Changes in total calcium levels can signal problems like vitamin D deficiency, thyroid disorders, or kidney function issues. High or low levels may also be linked to certain medications or cancers.

Short name

Total Calcium

Frequently asked questions

What causes abnormal calcium levels?
Abnormal calcium levels can result from dietary factors (e.g., low calcium intake), kidney problems, hormonal imbalances, or certain medications. Symptoms may include fatigue, bone pain, or unusual heart rhythms.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status, symptoms, and any ongoing conditions. Regular monitoring may be recommended if you have chronic kidney disease, osteoporosis, or other risk factors.
Can diet affect calcium test results?
Yes, your diet can influence calcium levels. Eating foods high in calcium (like dairy, leafy greens) or low in calcium (like excessive caffeine or alcohol) may temporarily affect results. Avoiding calcium supplements before the test can help ensure 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