Ca++
The biologically active fraction of blood calcium.
What is it
Ionized calcium is the unbound, biologically active form of calcium in circulation. It is more clinically informative than total calcium in many situations.
Why it's measured
Ionized calcium has been used in research on parathyroid function, bone metabolism, and acid-base balance.
Reference range
Standard laboratory reference
4.6 – 5.3 mg/dL
Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.
What results may indicate
Elevated
Has been associated with parathyroid disorders and certain malignancies in research literature.
Lower
Has been associated with parathyroid dysfunction and vitamin D deficiency in research literature.
These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.
When it's measured
Used when calcium status requires precise evaluation.
Related markers
Measured in
A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.
Explore the Apex Panel →This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.