Question

A sample of cerebrospinal fluid is diluted 1:100; the standard 9 squares of a hemocytometer are counted on each side for a total of 18 large squares

Side 1 - 186 nucleated cells counted
Side 2 - 184 nucleated cells counted
Total nucleated cells = 370
Using the standard hemocytometer formula, what is the nucleated cell count per microliter?
a. 1.03×10^4
b. 2.06×10^4
c. 4.12×10^4
d. 8.24×10^4

Answer 1

Using the hemocytometer formula, the nucleated cell count per microliter is calculated to be 2.06×10^4 cells/µL, matching closest to option b.

Step-by-step explanation:

To calculate the nucleated cell count per microliter using the standard hemocytometer formula, we take into account the total number of nucleated cells counted, the dilution factor, and the volume measured by the hemocytometer. The total number of cells is 370, as counted in 18 large squares (186 on side 1 and 184 on side 2). The standard formula is (total cell count × dilution factor) / (number of squares counted × volume per square). Here, the dilution factor is 100, and typically the volume for one large square of the hemocytometer is 0.1µL, hence the calculation is:

(370 cells × 100) / (18 squares × 0.1µL) = 37000 / 1.8µL = 20555.56 cells/µL

The closest answer provided in scientific notation is option b. 2.06×104 cells/µL.