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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 ensure your body’s vital functions run smoothly."]

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

Key facts at a glance

LOINC
60599-8
Short code
Face L1 to chin Skull XR
Synonyms
Face L1 to chin 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 Is This Test Done?

Your healthcare provider 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 Does the Test Involve?

A blood sample is taken from a vein, usually in your arm. The blood is then sent to a lab for analysis. The test measures the total calcium concentration in your serum.

What Are Common Causes?

Low calcium levels (hypocalcemia) can result from conditions like vitamin D deficiency, kidney problems, or certain medications. High calcium levels (hypercalcemia) may be linked to overactive thyroid, cancer, or prolonged bed rest.

What Are Normal Results?

Normal results vary slightly by lab and method, but typical ranges are often between 8.5 and 10.5 milligrams per deciliter (mg/dL) for adults. Your results will be compared to these standards.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal calcium levels can cause serious health issues. Low calcium can weaken bones, lead to muscle cramps, or affect nerve function. High calcium can weaken bones over time, cause kidney stones, or lead to fatigue or heart problems. Regular monitoring helps manage these risks.

Short name

Total Serum Calcium

Frequently asked questions

What does a low or high calcium level mean?
A low calcium level may indicate conditions like vitamin D deficiency, kidney disease, or certain medications that interfere with calcium absorption. A high level could suggest overactive thyroid, cancer, or prolonged dehydration. Your doctor will discuss these findings with you.
How often should I get this test?
Your doctor will determine how often you need this test based on your health history, symptoms, and other tests. Some people may need it yearly, while others may need it more or less frequently depending on their condition.
Can I eat or drink anything before the test?
You can usually eat and drink normally before this test unless your doctor instructs otherwise. Some tests may require fasting, but calcium tests typically do not.
  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