Peripheral Blood Smear
Definition
A blood sample is spread onto a slide, stained with a special dye, and examined under a microscope. Red blood cells, white blood cells, and platelets are evaluated for size, shape, and number.
Purpose
Used in the diagnosis and monitoring of blood and bone marrow disorders, certain cancers affecting the blood and lymphatic system, and parasitic diseases such as malaria and babesiosis. It is usually ordered in the following situations:
- When complete blood count results are abnormal
- With symptoms suggesting a blood cell disorder, such as fatigue, jaundice, unusual bleeding, fever, or bone pain
- To monitor treatment effectiveness in blood disorders
- To evaluate symptoms of a parasitic disease (especially in areas where the disease is common)
Results
| Cell | What an abnormality may suggest |
|---|---|
| Red blood cell | Anemia, sickle cell anemia, thalassemia, hemolytic anemia |
| White blood cell | Infection, leukemia, bone marrow disorders |
| Platelet | Thrombocytopenia, thrombocytosis, thrombocythemia |
Risks and Limitations
A peripheral blood smear alone cannot establish a diagnosis; it is evaluated together with other tests.
No special preparation is needed, unless another test ordered at the same time requires fasting.