In performing a manual white blood cell count, the sample is placed on a hematocytometer and counted using which objective?

In performing a manual white blood cell count, the sample is typically counted using the 10X objective lens on a hematocytometer. This magnification allows for a clear view of the cells while providing a sufficiently broad field of vision to accurately count the different types of white blood cells present in the sample.

Using 10X magnification strikes a balance between detail and field size, making it easier to distinguish individual cells without losing track of the overall number of cells in the designated counting area. Higher magnification objectives, such as 40X or 100X, would provide more detail but limit the field of view, making it more difficult to count the cells accurately and efficiently. Lower magnifications, like 5X, do not provide enough detail to count white blood cells effectively, as the image would not be sufficiently clear for precise counting tasks. Thus, the 10X objective is optimal for this procedure.