How is the number of platelets calculated from a blood smear?

The calculation of platelet count from a blood smear often involves evaluating several fields of view under a microscope to get an average platelet count. The method used typically includes counting the number of platelets within a specific area of the smear and then applying a conversion factor that correlates to the total volume of blood represented by that field.

In this scenario, the factor of 15,000 is commonly used in laboratory practices to estimate the total number of platelets per microliter of blood based on the count in microscopic fields. This factor derives from the relationship between the volume of blood sampled and the areas counted; it reflects the typical density of platelets seen per field under the microscope.

Using this conversion factor allows for a standardized estimate of platelet density in the overall blood sample, providing a clinically relevant measurement that aids in diagnosis and management. Thus, multiplying the count observed in a field by 15,000 provides a more accurate representation of the whole blood platelet concentration, making the answer valid for this context.