Red blood cells normally are the same in size and color and have a lighter-colored area in the center. The blood smear is considered normal if there is:

• Normal appearance of cells
• Normal white blood cell differential

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Abnormal results mean there is an abnormality in the size, shape, color, or coating of the red blood cells.

Some abnormalities may be graded on a 4-point scale:

• 1+ means 25% of cells are affected
• 2+ means half of cells are affected
• 3+ means 75% of cells are affected
• 4+ means all of the cells are affected

The presence of target cells may be due to:

• Decreased osmotic fragility
• Deficiency of an enzyme called lecithin cholesterol acyl transferase
• Hemoglobin abnormalities (hemoglobinopathies)
• Iron deficiency
• Liver disease
• Spleen removal
• Thalassemia

The presence of sphere-shaped cells (spherocytes) may be due to:

• Autoimmune hemolytic anemia
• Hereditary spherocytosis
• Increased osmotic fragility

The presence of elliptocytes may be a sign of hereditary elliptocytosis or hereditary ovalocytosis.

The presence of fragmented cells (schistocytes) may be due to:

• Artificial heart valve
• Disseminated intravascular coagulation
• Hemolytic uremic syndrome (HUS)
• Microangiopathic hemolytic anemia
• Thrombotic thrombocytopenic purpura (TTP)

The presence of a type of immature red blood cell called a normoblast may be due to:

• Cancer that has spread to bone marrow
• Erythroblastosis fetalis
• Leukoerythroblastic anemia (myelophthisis process)
• Miliary tuberculosis
• Myelofibrosis
• Removal of spleen
• Severe hemolysis
• Thalassemia

The presence of burr cells (echinocytes) may indicate:

• Uremia

The presence of spur cells (acanthocytes) may indicate:

• Abetalipoproteinemia
• Severe liver disease

The presence of teardrop-shaped cells may indicate:

• Leukoerythroblastic anemia
• Myelofibrosis
• Severe iron deficiency
• Thalassemia major

The presence of Howell-Jolly bodies may indicate:

• Myelodysplasia
• Post-splenectomy
• Sickle cell anemia

The presence of Heinz bodies may indicate:

• Alpha thalassemia
• Congenital hemolytic anemia
• G6PD deficiency
• Unstable form of hemoglobin

The presence of slightly immature red blood cells (reticulocytes) may indicate:

• Anemia with bone marrow recovery
• Hemolytic anemia
• Hemorrhage

The presence of basophilic stippling may indicate:

• Lead poisoning
• Myelofibrosis
• Myelophthisic process

The presence of sickle cells may indicate sickle cell anemia.