From the Research
Polychromasia and target cells on a complete blood count (CBC) are indicative of specific blood abnormalities that require further investigation, particularly to rule out hemoglobinopathies such as thalassemia and sickle cell disease, as suggested by studies like 1. These findings can be associated with various conditions, including liver disease, post-splenectomy states, and certain metabolic disorders. Polychromasia refers to the presence of immature red blood cells (reticulocytes) that appear bluish on a blood smear due to residual RNA, suggesting increased red blood cell production in response to blood loss, hemolysis, or recovery from anemia. Target cells, also called codocytes, are red blood cells with a central concentration of hemoglobin surrounded by a pale ring and a colored outer edge, resembling a bullseye.
When these abnormalities appear together on a CBC, additional testing is recommended, including:
- Hemoglobin electrophoresis to identify abnormal hemoglobin variants, as seen in conditions like sickle cell disease, where the ability to interpret hemoglobin electrophoresis can help clinicians distinguish between severe delayed hemolytic transfusion reaction and hyperhemolysis syndrome 2.
- Liver function tests to assess for liver disease.
- Possibly iron studies to evaluate for iron overload or deficiency, which can be particularly relevant in conditions like thalassemia, where iron chelation therapy is a common treatment approach 1.
The presence of both polychromasia and target cells often suggests an ongoing process affecting red blood cell production or destruction, and the underlying cause should be identified to guide appropriate treatment. Clinical correlation with the patient's symptoms, medical history, and other laboratory findings is essential for accurate diagnosis. Given the potential for these findings to indicate serious underlying conditions, prompt further evaluation and management are crucial to improve patient outcomes in terms of morbidity, mortality, and quality of life.