In counting WBCs for estimation, what magnification is typically used to count WBCs per field?

In counting WBCs for estimation, what magnification is typically used to count WBCs per field?

• A. 4x
• B. 10x
• C. 40x
• D. 100x

Answer: (C)

Counting WBCs per field is most reliable when you view the slide at 40x objective (about 400x total with a standard 10x ocular). This magnification gives enough detail to clearly identify leukocytes while keeping a field size that provides a representative sample of cells. At lower magnifications, distinguishing WBCs from RBCs becomes difficult and the field may be too crowded for accurate estimation. At higher magnification, you’ll see cells very clearly, but the field is smaller and counting becomes time-consuming, which isn’t efficient for quick estimation. That balance is why 40x is typically used.

Counting WBCs per field is most reliable when you view the slide at 40x objective (about 400x total with a standard 10x ocular). This magnification gives enough detail to clearly identify leukocytes while keeping a field size that provides a representative sample of cells. At lower magnifications, distinguishing WBCs from RBCs becomes difficult and the field may be too crowded for accurate estimation. At higher magnification, you’ll see cells very clearly, but the field is smaller and counting becomes time-consuming, which isn’t efficient for quick estimation. That balance is why 40x is typically used.