Skip to content

Calcium in Serum (Total)

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

This test measures the amount of calcium present in your blood serum. Calcium is an essential mineral that helps with muscle and nerve function, bone health, and blood clotting.

Quick summary

["Your blood calcium levels help ensure proper bodily functions and bone strength."]

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

Key facts at a glance

LOINC
35960-4
Short code
CT Clavicle
Synonyms
CT Clavicle
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
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, weakness, bone pain, or frequent fractures. It could also be done to check for conditions like kidney disease, low thyroid function, or certain cancers that affect calcium metabolism.

What to Expect Before the Test

No special preparation is needed for this test. You may have a small needle inserted into your arm to draw blood, and you’ll feel a brief pinch. If you’re on certain medications (like some heart or blood pressure drugs), let your doctor know beforehand.

What the Results Mean

Results are typically reported as a numerical value (in mg/dL or mmol/L), but your doctor will interpret them based on your overall health. Very high or very low levels can indicate underlying health issues.

Common Conditions Affecting Results

Abnormal calcium levels can be linked to conditions like hypoparathyroidism (low calcium), hyperparathyroidism (high calcium), kidney problems, or certain cancers. Your doctor will consider your symptoms and other test results for diagnosis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Total Serum Calcium

Frequently asked questions

How often will I need this test?
This test is often done as part of routine check-ups or when symptoms suggest calcium-related issues. Frequency depends on your health status and doctor’s recommendations—some people need it yearly, while others may need it less often.
What if my results are out of the normal range?
If your results are abnormal, your doctor will discuss them with you and may order additional tests or treatments. For example, low calcium might lead to supplements or medication adjustments, while high calcium could require lifestyle changes or further evaluation.
Can diet or supplements affect this test?
Yes, certain foods (like dairy, leafy greens) and supplements (like calcium or vitamin D) can influence calcium levels. Avoid taking large doses of calcium supplements 24 hours before your test, as this may affect accuracy.
  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