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Calcium, Serum or Plasma Mass Concentration

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

This test measures the amount of calcium, a mineral essential for bone health and many other body functions, in your blood.

Quick summary

["Your calcium levels help ensure strong bones and proper nerve and muscle function."]

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

Key facts at a glance

LOINC
2126-1
Short code
Citrate Smn-mCnc
Synonyms
Citrate Smn-mCnc
Category
chemistry
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

Why Is This Test Done?

Doctors may order a calcium test to check for conditions like low or high calcium (hypocalcemia or hypercalcemia), bone diseases, kidney problems, or metabolic disorders. It can also be part of routine health checks or when symptoms like muscle cramps, fatigue, or heart issues appear.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it involves drawing blood. Wear a loose shirt for easy access to your arm.

How the Test Is Performed

A healthcare provider will draw blood from a vein in your arm using a needle. You may feel a small pinch, but it’s over quickly. The blood sample is sent to a lab for analysis.

What the Results Mean

Results are compared to standard reference ranges, but exact values can vary by lab. Low calcium may cause weakness or numbness, while high levels could lead to kidney stones or heart issues. Your doctor will interpret results in the context of your health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal calcium levels can signal underlying health issues, such as thyroid disorders, vitamin D deficiency, or kidney disease. Regular monitoring is important for patients with chronic conditions like osteoporosis or those on long-term medications that affect calcium metabolism.

Short name

Calcium Level

Frequently asked questions

What causes low calcium levels?
Low calcium (hypocalcemia) can result from conditions like vitamin D deficiency, kidney problems, or certain medications. It may also occur after surgery, severe vomiting, or prolonged diarrhea.
What causes high calcium levels?
High calcium (hypercalcemia) can be caused by overactive thyroid, bone diseases, or kidney disorders. It may also appear in people with certain cancers or long-term use of some medications.
How often should I get this test?
Your doctor will determine how often you need this test based on your health history, symptoms, and risk factors. Routine adults may not need it unless recommended for specific conditions.
  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