Final answer:
To estimate platelet count on a blood smear, a standard practice is to count platelets in at least 10-20 fields using an oil immersion lens and a systematic approach to ensure accurate assessment. This count helps identify the presence and proportion of platelets and other formed elements in the blood.
Step-by-step explanation:
To determine the number of platelets on a differential blood smear, a minimum number of microscopic fields must be counted. While specific numbers may vary depending on institutional protocols, a common practice is to count the platelets in at least 10-20 fields to get a reliable estimate.
After staining, the smear is observed with a light microscope using the oil immersion objective lens. To assess platelet count accurately, it is important to use a systematic approach, such as a scanning pattern, ensuring that the entire slide is examined without duplication of fields.
The scanning process might involve identifying and counting each white blood cell until reaching a certain number, like 100 cells, to also classify the white blood cells. Along with the white blood cells, platelets should be counted in the same manner.
A more in-depth analysis of the blood smear may provide insights into the presence of various formed elements in the blood, including platelets, and can indicate if the numbers are within the normal range or if there are abnormalities.