Calciumrbcscnc
A blood test that measures the amount of calcium inside your red blood cells to help evaluate your body's calcium status.
{"Measures calcium levels inside red blood cells","Requires a simple blood sample","Helps diagnose conditions affecting calcium balance","May be used to monitor certain treatments"}
Key facts at a glance
- LOINC
- 25583-6
- Short code
- RBC Ca
- Synonyms
- Calcium RBC-sCnc
- Category
- electrolyte
- Sample
- whole-blood
- Container
- Lavender top (K2-EDTA) tube or royal blue top (EDTA) trace metal-free collection tube
- Units
- not specified
- Ref low
- 0.015
- Ref high
- 0.025
- Critical range
- 0.3 not specified – 1.5 not specified
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 18 years
- Method
- Atomic Absorption Spectroscopy (AAS) or Inductively Coupled Plasma Mass Spectrometry (ICP-MS)
- CPT
- 82310
- SNOMED
- 271583001
- Specimen volume
- 2-3 mL whole blood
- Stability
- Room temperature: 7 days; Refrigerated (2-8°C): 14 days; Avoid freezing whole blood specimen
- Hemolysis max
- 50
- Lipemia max
- 300
- Icterus max
- 20
- TAT
- 24–72 hours
- Order
- routine
What is this test?
The Red Blood Cell Calcium test measures the amount of calcium present inside your red blood cells (erythrocytes). While most routine calcium tests measure calcium in the liquid part of your blood (serum), this test specifically looks at intracellular calcium—the calcium contained within the cells themselves. This can provide different and sometimes more accurate information about your body's calcium status, especially in certain medical conditions.
Why is it ordered?
Your healthcare provider may order this test to: evaluate calcium metabolism disorders, investigate conditions that affect cell membrane function, assess certain kidney diseases, monitor patients on long-term dialysis, or investigate unexplained fatigue, muscle weakness, or abnormal heart rhythms. It may also be useful in monitoring the effectiveness of calcium supplements or other treatments.
How is the test performed?
A healthcare professional will draw a small sample of blood from a vein in your arm using a needle. The sample is then processed in a laboratory to separate the red blood cells and measure the calcium content within them. The procedure is quick and similar to other routine blood tests.
How to prepare
Follow your healthcare provider's instructions regarding fasting or medication adjustments. Some medications may affect calcium levels, so inform your doctor about all medications and supplements you are taking. No special preparation is usually required beyond following your provider's specific instructions.
Reference range
0.015-0.025 mmol/Lnot specified
No special preparation or fasting required
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Is this test different from a regular calcium blood test?
Do I need to fast before this test?
What do abnormal results mean?
Are there any risks from this test?
Sources
- 1
- 2
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 10, 2026. · Read our editorial policy