Red blood cell (RBC) morphology with automated microcytometry (qualitative assessment of RBC size distribution)
This test evaluates the range of red blood cell sizes in your blood, which can help identify whether some cells are unusually small or large.
["Assessing RBC size variability may help diagnose conditions affecting blood cell production or function."]
Key facts at a glance
- LOINC
- 33666-9
- Short code
- Dysmorphic RBC # Ur Micro
- Synonyms
- Dysmorphic RBC # Ur Micro
- 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
- microscopy-light
- 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
Why This Test Is Done
Your healthcare provider may order this test if you have symptoms like fatigue, pale skin, or unusual bruising, or if tests show low red blood cell counts. It can also be part of routine screening for certain blood disorders.
What to Expect Before the Test
No special preparation is needed. A simple blood draw from a vein in your arm is all that’s required. The test measures RBC size using advanced technology that analyzes thousands of cells at once.
How the Results Are Interpreted
Results typically show whether most RBCs fall within a normal size range or if there’s a shift toward smaller (microcytic) or larger (macrocytic) cells. Abnormal patterns may signal conditions like iron deficiency, anemia, or genetic disorders.
Common Conditions Linked to Abnormal RBC Sizes
Microcytosis (small RBCs) may indicate iron deficiency, thalassemia, or chronic diseases. Macrocytosis (large RBCs) can suggest vitamin deficiencies (like B12 or folate), liver disease, or alcohol use.
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.
Clinical Significance: Abnormal RBC size patterns often point to underlying health issues that require further investigation, such as blood disorders, nutritional deficiencies, or chronic illnesses. Early detection can guide treatment decisions.
Short name
RBC Size Distribution Check
Frequently asked questions
What causes RBC size variability to be checked?
How long does it take to get results from this test?
Can lifestyle changes affect RBC size measurements?
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