The effect of anticoagulants on the size of platelets in blood smears in the course of time.

In this study we measured platelet size in blood smears using the Kontron Mop Videoplan (Kontron Electronic Group, Weesp, Holland). The blood smears were prepared at different times after phlebotomy; samples were collected in three different anticoagulants and 100 consecutive platelets were measured in each smear. A number of platelet parameters were determined, some of which were based on the log normal distribution of the platelet area. We found that the size of platelets in blood smears is also dependent on the time after phlebotomy and the anticoagulant used. This may be important for the comparison of platelet areas, a characteristic of various disorders. Our data indicate that the optimal interval after phlebotomy for preparation of blood smears is 2-5 min.