Figure 13. Counting platelets using the ImageJ multi-point tool.

A. Platelets are counted on the DIC channel. B. The platelets are verified using the fluorescence channel to check for anti-GPIb-488 staining. Clicking on an image, with the multi-point tool selected, will leave a marker with a number on the image. Holding “alt” and then clicking on a marker will remove the marker. Each subsequent click or removal will increase or decrease the number on the marker by one respectively. Use this feature to count the number of platelets on the image. Alternatively, after clicking on each platelet on the image, use the counter on the point tool window (Figure 12) to determine the number of platelets counted.