Red Blood Cell Area Ratio (Autoanalyzer-based measurement)
This test measures the average size of red blood cells (RBCs) by analyzing their geometric area, often used in conjunction with other blood tests to assess red blood cell health or potential abnormalities.
["Helps doctors evaluate RBC size variations that may indicate conditions like anemia or iron deficiency."]
Key facts at a glance
- LOINC
- 46419-8
- Short code
- RBC #/area UrnS Auto
- Synonyms
- RBC #/area UrnS Auto
- Category
- chemistry
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Ref low
- 4.2
- Ref high
- 5.9
- Critical range
- 2 N/A – 7 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- automated-count
- CPT
- 85041
- SNOMED
- 900000000000003001
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What Does This Test Measure?
The test calculates the average area of red blood cells using automated technology. While RBCs typically vary slightly in size, consistent changes can signal underlying health concerns. This measurement is part of a broader assessment of blood cell morphology and function.
Why Might You Need This Test?
Doctors may order this test if you have symptoms like fatigue, pale skin, or unusual bruising, or if they suspect conditions like anemia, thalassemia, or other blood disorders. It can also be part of routine blood work to monitor chronic conditions.
How Is the Test Performed?
A small blood sample is drawn from a vein, usually in your arm. The sample is then processed in a laboratory to measure RBC area automatically. The results are compared to standard values to determine if further investigation is needed.
What Are Possible Results?
Results are expressed as a ratio or index, reflecting the average RBC area. While specific reference ranges can vary by lab, deviations from typical values may prompt additional tests to explore potential causes.
Reference range
Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
RBC Area Ratio
Frequently asked questions
What causes RBC area variations?
Is this test painful?
How long does it take to get results?
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