Red Blood Cell Morphology, Peripheral Blood Smear
This test examines red blood cells under a microscope to evaluate their size, shape, color, and other structural features. It is often used alongside a complete blood count to help identify and monitor blood disorders.
["A blood smear can reveal changes in red blood cell shape or structure that may help diagnose anemia, bleeding disorders, or other blood conditions."]
Key facts at a glance
- LOINC
- 75819-3
- Short code
- RBC Chrm Bld Smear
- Synonyms
- RBC Chrm Bld Smear
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- 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
- microscopy-light
- CPT
- 85041
- SNOMED
- 900000000000003001
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What the test checks
A small drop of blood is spread across a slide and examined under a microscope. The laboratory looks for red blood cells that differ in size, shape, color, or internal appearance, as well as abnormal cells or substances.
Why it is performed
A blood smear may be ordered when a complete blood count shows anemia, an abnormal cell count, or other concerning results. It can also help evaluate unexplained symptoms such as fatigue, weakness, shortness of breath, bruising, or yellowing of the skin or eyes.
What the results mean
Abnormal red blood cells can be associated with nutritional deficiencies, inherited blood disorders, immune-related problems, bleeding conditions, liver disease, or other illnesses. Results should be interpreted with the complete blood count, medical history, and other appropriate tests.
Limitations and preparation
No special preparation is usually required, and the test is generally performed by drawing blood from a vein. A blood smear provides useful visual information, but it does not by itself identify the exact cause of an abnormal finding.
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 morphology on blood smear
Frequently asked questions
Is a blood smear the same as a complete blood count?
Does the test require fasting?
What if my results are abnormal?
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