Calcium concentration in serum/plasma (calculated from ionized calcium and albumin)
This test estimates your total calcium level in your blood by adjusting for protein levels, specifically albumin. Calcium is an essential mineral that helps with muscle and nerve function, bone health, and blood clotting.
["Your doctor may use this test to check if your calcium levels are balanced, especially if you have conditions like kidney disease, low or high thyroid hormone, or certain medications."]
Key facts at a glance
- LOINC
- 11151-8
- Short code
- Hct VFr BldCo Calc
- Synonyms
- Hct VFr BldCo Calc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 36
- Ref high
- 50
- Critical range
- 18 N/A – 60 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- calculated
- CPT
- 85014
- 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 Matters
Calcium is vital for many body functions, but too much or too little can cause health problems. This test helps ensure your calcium levels stay within a healthy range, supporting everything from muscle movement to bone strength.
How the Test Works
Your blood sample is analyzed to measure two key parts: ionized calcium (the active form) and albumin (a protein that binds calcium). The test then calculates the total calcium level based on these measurements.
What to Expect Before the Test
No special preparation is needed for this test. You may have a small needle inserted into your arm to draw blood, which usually causes only mild discomfort. If you’re on blood thinners or have a history of bleeding, let your doctor know.
Possible Results and Their Meaning
Results are reported as a calculated value, not a single number. If your levels are too high or too low, your doctor may recommend further testing or adjustments to your treatment plan.
Reference range
Adult males: 38-50%; Females: 36-44%N/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Calcium Calculation
Frequently asked questions
What could cause abnormal results?
How often should I get this test?
Can diet or supplements affect this test?
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 17, 2026. · Read our editorial policy