What is the name of the procedure in which a blood smear from a finger is stained and observed under a microscope to determine the number and type of leukocytes?

The procedure being referred to is indeed known as a differential count. This process involves taking a sample of blood—often through a fingerstick—to create a smear on a glass slide, which is then stained using specific dyes. The stained blood smear allows for the detailed observation of the various types of leukocytes (white blood cells) present in the sample.

This analysis is crucial for identifying abnormalities in white blood cell types and overall leukocyte counts, which can provide valuable insights into a patient's immune status and help in diagnosing various medical conditions, including infections, allergies, and hematologic disorders.

Other procedures listed, such as blood typing and complete blood count, focus on different aspects of blood analysis. Blood typing identifies blood group characteristics, while a complete blood count measures several blood elements including red blood cells, hemoglobin levels, and platelets, but does not provide the detailed classification of white blood cells that a differential count offers. Hemoglobin electrophoresis is used for analyzing the different types of hemoglobin in blood, unrelated to leukocyte assessment.