3.2 An example cell count

In this short video, I will be explaining how to do a differential leukocyte count on normal blood. Specifically, I am looking for neutrophils, lymphocytes, monocytes, eosinophilic, and basophils.

I have the normal blood smear loaded on the microscope stage. I'm going to use the times 20 objective because that allows me to distinguish the cell types, and gives me a reasonable area to look at. I'm also going to add the grid to help with counting. And I'm going to start near the top left of the section.

Here, I can see one, two neutrophils, and one lymphocyte. I'm going to scan across the section, looking specifically for cells that lie between the upper and lower heavier grid lines. Another neutrophil. Two more neutrophils.

This one is a monocyte. There's a small lymphocyte. Once I reach the end, I'm going to drop down to a lower line and scan back, making sure not to count the same cells twice. And carrying on as before. There's a lymphocyte, and an eosinophil, and so on, until I've counted 100 cells.

Now at this stage, I would tally up the cells of each time. And as you can see, it falls within the normal range.