What type of field is used to count platelets?

What type of field is used to count platelets?

• A. Oil-immersion fields
• B. Light microscope fields
• C. Electron microscopy fields
• D. Dissecting microscope fields

Answer: (A)

When counting platelets, you view the sample in oil-immersion fields. Platelets are extremely small, so you need the high resolution of a 100x objective with immersion oil to distinguish individual platelets clearly in a hemocytometer. The oil reduces light refraction and improves clarity, which is essential for accurate counting in defined fields. Other microscope field types don’t provide enough detail for platelets—the standard light-field without oil lacks the resolution, electron microscopy is far more advanced than needed for routine counts, and dissecting microscopes are not suitable for counting such tiny cells. After counting in several oil-immersion fields, you use the average count, the dilution factor, and a conversion factor (typically 10^4) to express the result as platelets per microliter.

When counting platelets, you view the sample in oil-immersion fields. Platelets are extremely small, so you need the high resolution of a 100x objective with immersion oil to distinguish individual platelets clearly in a hemocytometer. The oil reduces light refraction and improves clarity, which is essential for accurate counting in defined fields. Other microscope field types don’t provide enough detail for platelets—the standard light-field without oil lacks the resolution, electron microscopy is far more advanced than needed for routine counts, and dissecting microscopes are not suitable for counting such tiny cells. After counting in several oil-immersion fields, you use the average count, the dilution factor, and a conversion factor (typically 10^4) to express the result as platelets per microliter.