HOW TO CALIBRATE YOUR MICROSCOPE.
Why is it important to calibrate each microscope?
Since no two microscopes are identical, assessing the same semen sample with different microscopes may yield different results. To adjust for differences between microscopes, a correction factor should be applied to ensure accurate sperm concentrations are obtained. The correction factor (F) must be determined for each objective used with the microscope.
To determine F, you will need a gridded eyepiece reticle or an eyepiece with a build-in grid, and a stage micrometer. All items can be purchased as starter-kit from your Leja distributor.
- Insert the eyepiece reticle (or use the auxiliary eyepiece provided with the microscope which includes a built-in reticle). Figure 1 shows the view through the eyepiece.
- Position the stage micrometer of the microscope tage so that the “0” value is lined up exactly with the edge of the reticle (see figure 2). The distance between the longer, numbered lines equals 100 μm.
- Measure the distance between the left and the right edges of the reticle. Mark this value as the “measured lentgh of square”.
- Remember the number of boxes on a single row you used to measure this, normally this is 10, but some grids have a 5 x 5 dimension.
Now use our handy on-line tool to calculate your correction fact F for this microscope and the used objective. repeat this step for each objective and micrscope you use and clearly mark this down somewhere.