A simple and easy method of counting blood platelets is greatly to be desired. The methods at present available are either too inaccurate or too difficult and time-consuming. The result is that platelet counts are not done as a routine and that our knowledge of their clinical significance is still rather meager.
The well known preservative effects of sodium citrate toward blood platelets suggested to us its use in counting them; and the obvious advantages of counting them in the same counting chamber as the red blood cells led us to devise what we believe to be the simplest and most accurate method.
This method has the advantage that it does not involve any additional step in a blood count, as the red cells are counted at the same time as the platelets. The trifling work required to count the platelets by this method should lead to the general adoption