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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 keeping your bones strong, muscles and nerves working properly, and for many other body functions.

Quick summary

["Your blood calcium levels help prevent conditions like osteoporosis or abnormal heart rhythms."]

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

Key facts at a glance

LOINC
60600-4
Short code
Face upper Skull XR
Synonyms
Face upper Skull XR
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-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 This Test Is Done

Doctors may order a total serum calcium test to check for conditions like low or high calcium levels, which can cause symptoms such as muscle cramps, weakness, confusion, or irregular heartbeat. It may also be done to monitor treatment for conditions like kidney disease, bone disorders, or certain cancers.

What to Expect Before the Test

You can eat and drink normally before the test. No special preparation is needed unless your doctor instructs otherwise. Bring any medications you’re currently taking, as some can affect calcium levels.

How the Test Is Done

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 much discomfort. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results are reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). While reference ranges vary by lab, low or high levels may signal underlying health issues that need further evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Total Serum Calcium

Frequently asked questions

What does a low calcium level (hypocalcemia) mean?
Low calcium levels can cause muscle spasms, numbness, irregular heartbeat, or seizures. It may also indicate conditions like vitamin D deficiency, kidney problems, or certain medications.
What does a high calcium level (hypercalcemia) mean?
High calcium levels can lead to fatigue, nausea, kidney stones, or weakened bones. It may result from overactive thyroid, cancer, or prolonged use of certain medications.
How often should I get this test?
Your doctor will determine how often you need this test based on your health needs, symptoms, or ongoing conditions. Regular monitoring may be needed if you have chronic kidney disease, bone disorders, or take calcium-regulating medications.
  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