Final answer:
To perform a differential blood cell count, the feathered edge of a Wright stained blood smear is used, with identification and counting of white blood cells performed using an oil immersion objective lens. At least 50 to 100 cells are counted systematically and recorded to assess blood distribution and detect any abnormalities.
Step-by-step explanation:
When performing a differential blood cell count, also known as Diff, it is essential to choose the appropriate portion of a blood smear for accurate results. After the slide is stained with Wright-Giemsa stain, which differentially stains red blood cells and the white blood cells, the slide should be observed under a microscope. The correct portion to use for a differential cell count is the feathered edge, which is the area where the blood film has a uniform thickness and cell distribution. Starting at the feathered edge, a systematic scanning pattern should be used to identify and count the white blood cells. This is often done until at least 50 to 100 white blood cells have been counted to determine if the numbers represent a normal blood distribution or if there are any abnormalities.
An initial scan using the oil immersion objective lens helps to evaluate the overall appearance of the blood cells, including red blood cells and platelets. Then, focus shifts to a more detailed analysis of the white blood cells. A simple table with each leukocyte type can aid in this process as each cell type is identified and tallied. Counting a proper mix of cell types is crucial to accurately assessing the individual's immune status or detecting any hematological abnormalities. The Wright stained blood smear provides clear visualization of the different blood cells, thus aiding in the identification and counting process.