SECTION 2 COUNTING THE CELLS

Principles of counting cells

Neubar grid

Grid dimensions

Counting large cells

Counting small cells

Quiz 1

Counting calculation

Quiz 2

TITLE: PRINCIPLES OF COUNTING CELLS

As with any lab technique there is a correct way to accurately count your cells. Aim for about 100 cells per count in your dilution. You may need to try out different dilutions first to obtain an appropriate cell number on the counting grid.

Count in a consistent manner – for example across rows or down columns. Use the following “in” and “out” assumptions, so you know what to do if cells overlap the grid lines. Cells that over lap the top and right grid lines are included in your count but those overlapping bottom and left are excluded. So in this example there are 6 cells.

Make multiple readings and average them to gain an accurate value. You must count both grids on the haemocytometer to check that your suspension is uniformly mixed. If the two grids give wildly different values then your suspension is not mixed and you will not gain an accurate value of cell number.