Blood Smear Examination

Examination of a blood smear is an integral part of a hemogram. Blood smear analysis allows quantitation of the different types of leukocytes (called the differential count), estimation of the platelet count, and detection of morphologic abnormalities that may be indicators of pathophysiologic processes. In some instances, a diagnosis may be evident. Deriving full value from blood smear examination requires a well-prepared, well-stained blood smear and some basic skills in the methods of assessment. Though some automated hematology analyzers provide a differential count as part of their ouput, this does not fully take the place of a microscopic exam by an experienced observer. A systematic approach is important so that all the available information is derived from each smear examined. Follow this protocol: Scan the smear at low magnification (10x objective) to locate the optimal area for examination at higher magnification, and check the feathered edge to evaluate the distribution of leukocytes on the smear Perform the differential count (100x objective) Assess platelet numbers (100x objective) Perform a morphologic assessment of blood cells (100x objective)

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Last Updated:Thursday, March 14, 1996