Question

When performing a manual white blood cell count, 236 cells were counted on side number one of the hemacytometer, 224 cells on side number two. A 1/20 dilution of 1% HCl was used and the area counted on each side was 4 sq mm. Twenty-five nucleated red blood cells in the differential were observed per 100 white blood cells. What is the CORRECT WBC/uL?

a. 8,500
b. 9,200
c. 9,575
d. 12,425

Answer 1

The correct white blood cell count (WBC/µL) calculated using a hemocytometer and considering the given cell counts, dilution factor, and area is 11,500 cells/µL, which does not match any of the provided choices.

Step-by-step explanation:

To calculate the correct white blood cell count (WBC/µL) using a hemocytometer, we need to combine the cell counts from both sides of the chamber, adjust for dilution factor, and divide by the total area counted. Here, 236 cells were counted on side one and 224 cells on side two, giving a total of 460 cells. As a 1/20 dilution was used and the area counted was 4 sq mm on each side (8 sq mm total), the calculation is as follows:

(460 cells counted / 8 sq mm) x (10 mm2/1 sq mm) x (1/20 dilution factor)-1 = 11,500 cells/µL

Note that the presence of nucleated red blood cells in the differential (25 per 100 WBCs) should not affect the calculation for total WBC count.

The correct answer to "What is the correct WBC/µL?" would be 11,500 cells/µL. However, since this option is not available in the given choices and considering it might be a typo or an issue with the provided choices, the best approach is to refuse to answer as none of the options given (a. 8,500 b. 9,200 c. 9,575 d. 12,425) match the calculated value.