Total Calcium with Ionized Calcium Ratio (Serum)
This test measures two key forms of calcium in your blood: the total calcium level and the ionized (active) calcium level. Calcium is essential for muscle function, nerve signaling, and bone health.
["Understanding both total and ionized calcium helps assess your body’s calcium balance and potential risks of conditions like low calcium or abnormal calcium levels."]
Key facts at a glance
- LOINC
- 37632-7
- Short code
- XR tomo Pelvis
- Synonyms
- XR tomo Pelvis
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- xr-tomography
- 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 healthcare provider may order this test if you have symptoms like muscle spasms, numbness, fatigue, or frequent bone pain. It may also be done to check for conditions like hypoparathyroidism, kidney disease, or metabolic bone disorders, or to monitor treatment for conditions affecting calcium levels.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it involves drawing blood, but this depends on your provider’s instructions. Stay hydrated unless advised otherwise.
What the Results Mean
Total calcium measures all forms of calcium in your blood, including bound and free forms. Ionized calcium is the active, free form that your body uses. Abnormal results may indicate conditions affecting calcium metabolism or kidney function.
Common Conditions Linked to These Results
Low ionized calcium (hypocalcemia) can cause muscle cramps, seizures, or irregular heart rhythms. High ionized calcium (hypercalcemia) may lead to fatigue, nausea, or kidney stones. Both extremes can signal underlying issues like vitamin D deficiency, kidney disease, or overactive thyroid.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Total Calcium & Ionized Calcium
Frequently asked questions
Will my results affect my medications?
Can I eat or drink anything before the blood draw?
What are the normal ranges for these tests?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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