Ionized Calcium
Ionized calcium measures the amount of free, active calcium in your blood that is not bound to proteins. It is the biologically active form and a more precise indicator of calcium status than total c…
Category: Metabolic Panel
Also known as: ionized calcium, free calcium, ica, ca2+, ca ionized, calcium ionized, Ca-I, Calcium active
Reference range: 4.5–5.3 mg/dL (Source: ABIM)
Standard unit: mg/dL
High values may indicate
High ionized calcium levels may indicate hyperparathyroidism, certain cancers, or excessive vitamin D intake.
Low values may indicate
Low ionized calcium levels may indicate hypoparathyroidism, vitamin D deficiency, sepsis, or complications from blood transfusions.
Frequently asked questions
- What is a normal Ionized Calcium level?
- A typical reference range for Ionized Calcium is 4.5–5.3 mg/dL (source: ABIM). Reference ranges vary by laboratory, age, and sex, so always compare against the range on your own lab report.
- What units is Ionized Calcium measured in?
- Ionized Calcium is most commonly reported in mg/dL. Labs in different countries may use other units — you can convert between them with BloodId's blood test unit converter.
- Where do Ionized Calcium reference ranges come from?
- BloodId uses ABIM standard reference ranges and educational information from MedlinePlus (see our methodology). Reference ranges still vary by lab, age, and sex, so always compare against your own report.
- Can I track Ionized Calcium over time?
- Yes. Upload results from any lab and BloodId charts your Ionized Calcium over time against its reference range, so you can see whether the trend is rising, falling, or stable.
Related biomarkers
Source: MedlinePlus, U.S. National Library of Medicine
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