Peripheral Blood Smear Examination (Qualitative Leukocyte Morphology)

Why Is This Test Done?

Your healthcare provider may order a peripheral blood smear if you have symptoms like fever, fatigue, weight loss, unexplained bruising, or recurrent infections. It’s also used to monitor conditions like leukemia, lymphoma, or autoimmune diseases. Sometimes, it’s part of a routine checkup or to investigate unexplained lab results.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your vein (usually in your arm) to draw a small amount of blood. The sample is then spread thinly on a microscope slide and examined under a microscope by a trained lab technician.

What Happens During the Test?

The blood sample is processed and stained to highlight different cell types. A technician examines the smear under a microscope, looking for normal or abnormal white blood cells, red blood cells, or platelets. Results are qualitative (descriptive) rather than numerical.

What Are the Possible Findings?

Normal findings show a mix of different white blood cell types, such as neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Abnormal findings may include an increased or decreased number of certain cells, unusual shapes, or signs of cell damage. For example, high numbers of immature white blood cells might suggest leukemia, while a high count of segmented neutrophils could indicate infection.