Question

What dilution is commonly used for counting WBCs and platelets on a hemocytometer?

A) 1:2 dilution
B) 1:10 dilution
C) 1:20 dilution
D) 1:50 dilution

Answer 1

A 1:20 dilution is commonly used for counting WBCs and platelets on a hemocytometer to get an accurate cell count.

Step-by-step explanation:

For counting white blood cells (WBCs) and platelets on a hemocytometer, a 1:20 dilution is commonly used. This dilution allows for an appropriate cell concentration that is neither too high, which could lead to overlap making counting difficult, nor too low, which could result in inaccurate counts due to an insufficient number of cells. This dilution is achieved by mixing 1.0 mL of the original culture with 19.0 mL of dilution solution. This step represents a dilution factor of 20 compared to the original culture. The use of a dilution factor is critical in obtaining an accurate estimate of the cell concentration in the original culture after performing either the pour plate or spread plate methods.