Skip to content

Calcium

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

A calcium test measures the amount of calcium in a patient sample, most commonly blood, to help evaluate calcium balance and bone, nerve, and muscle function.

Quick summary

["This test helps assess calcium balance and may be used to investigate symptoms involving bones, muscles, nerves, or heart rhythm."]

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

Key facts at a glance

LOINC
101001-6
Short code
Chief Architect+Leader of LOINC
Synonyms
Chief Architect+Leader of LOINC
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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

What is this test?

A calcium test measures the amount of calcium in a patient sample. In most clinical settings, the sample is blood, but the supplied test slug does not specify a specimen or method.

Why might I need this test?

Calcium testing may help assess calcium balance and support evaluation of conditions that affect the bones, kidneys, nerves, muscles, or parathyroid glands. It may also be included as part of a broader metabolic panel.

How is the test performed?

A blood sample is usually collected with a needle and sent to a laboratory for measurement. The laboratory method may vary, and the sample may measure total calcium or a different form of calcium.

How do I prepare for the test?

Fasting is generally not required, but follow the instructions provided with your order. Tell the healthcare professional if you are pregnant, have kidney disease, or take medicines that may affect calcium levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A low calcium level may be associated with inadequate parathyroid hormone, vitamin D deficiency, kidney disease, or certain other conditions. A high calcium level may occur with parathyroid or kidney disorders, vitamin D excess, dehydration, or certain medicines. Results should be interpreted with the specimen type, laboratory method, symptoms, and other laboratory findings.

Short name

Calcium

Frequently asked questions

Does this test measure total calcium or ionized calcium?
The supplied slug does not specify the method or specimen, so it may represent a general calcium test. Total calcium and ionized calcium are related but are different measurements.
Do I need to fast before a calcium test?
Fasting is usually unnecessary unless your healthcare professional specifically requests it. Follow the preparation instructions for your particular order.
Can medicines affect the result?
Yes. Vitamin D, diuretics, calcium-containing products, and some other medicines can alter calcium levels. Do not stop prescribed medicines without discussing them with your healthcare professional.
  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