Anisocytosis and abnormal RBC morphology: what the lab comment means

Anisocytosis and Abnormal RBC Morphology: What Your Lab Comment Means

When your lab report mentions anisocytosis or abnormal red blood cell (RBC) morphology, it’s flagging a variation in the size, shape or appearance of your red blood cells. Understanding what these findings mean can help you and your doctor figure out whether further testing or treatment is needed. Below is a straightforward guide based on credible medical sources.

What Is Anisocytosis?
Anisocytosis literally means “unequal cells.” In healthy blood, most RBCs are roughly the same size. Anisocytosis reflects a wider range of cell sizes, often reported by your lab as an elevated RDW (red cell distribution width) on a complete blood count (CBC).

• RDW-CV or RDW-SD high: signals more variation in RBC size.
• Degree of anisocytosis: mild, moderate or marked, depending on how much sizes differ.

What Is Abnormal RBC Morphology?
Abnormal RBC morphology refers to any atypical feature seen when a drop of your blood is examined under a microscope (peripheral smear). Your lab may report:

• Poikilocytosis – variation in RBC shape (e.g., teardrop cells, target cells)
• Polychromasia – young RBCs that stain bluer than mature cells
• Spherocytes – round, densely stained RBCs without the normal central pale area
• Elliptocytes – elongated or oval RBCs
• Schistocytes – fragmented RBCs

Does Anisocytosis Cause Abnormal RBC Morphology?
While anisocytosis and abnormal morphology often appear together, one doesn’t directly “cause” the other. Instead, both reflect disturbances in how red blood cells form, mature or survive.

• Anisocytosis is about variation in size.
• Morphologic changes are about shape, color or structure.
• Shared underlying causes (e.g., nutrient deficiencies, bone marrow stress) lead to both findings.

Common Causes of Anisocytosis and Abnormal Morphology

1. Nutrient Deficiencies
   • Iron deficiency: small (microcytic), pale (hypochromic) RBCs + high RDW
   • Vitamin B12 or folate deficiency: large (macrocytic), oval RBCs + high RDW

2. Hemolytic Processes
   • Autoimmune hemolysis: fragmented cells (schistocytes), spherocytes
   • Mechanical destruction (prosthetic heart valves): schistocytes

3. Bone Marrow Disorders
   • Myelodysplastic syndromes: variable sizes and shapes, sometimes blasts
   • Aplastic anemia: overall low cell counts; occasional abnormal shapes

4. Chronic Disease or Inflammation
   • Anemia of chronic disease: mild anisocytosis, sometimes target cells

5. Liver or Kidney Disease
   • Liver disease: spur cells (acanthocytes), target cells
   • Kidney disease: burr cells (echinocytes)

6. Hemoglobinopathies
   • Sickle cell disease: sickle-shaped cells, target cells
   • Thalassemia: target cells, microcytosis, elevated RDW

How a Lab Comment Guides Next Steps
When your report notes anisocytosis or abnormal RBC morphology, it’s a signal to your doctor to:

1. Correlate with symptoms
   • Fatigue, shortness of breath, pale skin → think anemia.
   • Jaundice, dark urine → think hemolysis.

2. Review other lab values
   • Hemoglobin, hematocrit, MCV (average RBC size), MCHC (color)
   • Reticulocyte count (immature RBC production)
   • Iron studies, B12, folate, liver enzymes

3. Consider a peripheral smear review
   • A trained technologist or hematologist examines a slide to confirm details.

4. Decide on further testing
   • Bone marrow biopsy if bone marrow disorder is suspected
   • Autoimmune antibody tests if hemolysis is suspected

Interpreting Specific Patterns
• High RDW + low MCV: classic for iron deficiency anemia.
• High RDW + high MCV: suggests B12 or folate deficiency.
• Normal RDW + low MCV: sometimes seen in thalassemia trait.
• Schistocytes present: point toward hemolytic anemia or microangiopathic processes (e.g., TTP, DIC).

What You Can Do Right Now
• Review your full blood count: note which values are outside the normal range.
• List any symptoms you have (tiredness, bleeding, bruising, etc.).
• Use a free, online symptom check, using the doctor approved Ubie Symptom Checker to get a preliminary sense of possible causes. (https://ubiehealth.com/)
• Gather information on your diet, medications and family history.

When to Speak to a Doctor
Most causes of anisocytosis and abnormal RBC morphology are treatable once identified, but some can be serious. Contact a healthcare provider promptly if you experience:
• Severe fatigue or shortness of breath at rest
• Chest pain, rapid heartbeat or lightheadedness
• Unexplained bruising, bleeding or persistent fever
• Yellowing of the eyes or skin (jaundice)

Treatment Approaches

1. Correct Nutrient Deficiencies
   • Iron supplements or dietary changes for iron deficiency
   • B12 injections or high-dose oral B12 for pernicious anemia
   • Folate supplements for folate deficiency

2. Manage Underlying Disorders
   • Immunosuppressive therapy for autoimmune hemolysis
   • Hydroxyurea or bone marrow transplant for sickle cell disease
   • Disease-modifying treatments for myelodysplastic syndromes

3. Supportive Measures
   • Blood transfusions in severe anemia
   • Folate-rich diet (leafy greens, beans, fortified cereals)
   • Iron-rich diet (red meat, spinach, legumes, fortified grains)

4. Monitor and Follow Up
   • Repeat CBC after 4–6 weeks of therapy to ensure response
   • Regular monitoring in chronic conditions (e.g., thalassemia)

Key Takeaways
• Anisocytosis = variation in RBC size; abnormal morphology = changes in shape or structure.
• Both findings flag potential issues with red blood cell production or survival.
• Common causes include nutrient deficiencies, hemolysis, bone marrow disorders and chronic disease.
• Your doctor uses these clues—along with symptoms and other labs—to pinpoint the underlying condition.
• Early evaluation and treatment often lead to full resolution or effective management.

If you have any concerns about lab findings or serious symptoms, speak to a doctor right away. A thorough evaluation will help rule out life-threatening causes and guide appropriate treatment.