Question

1. Calculate the following white cell count if the dilution of 1/100. Show your calculations. (3pts)

Side #1                                                               Side #2

Square 1 = 30 white cells             Square 1 = 27 white cells

Square 2 = 28 white cells             Square 2 = 27 white cells

Square 3 = 25 white cells             Square 3 = 24 white cells

Square 4 = 27 white cells             Square 4 = 24 white cells

Answer 1

We have, side of one primary square = 1 mm

Therefore, side of one secondary square = 1/4 mm

Now, area of one secondary square = (14) (14) = 1/16 mm2

We have, depth of one secondary square = 1/10 mm

Therefore, volume of one secondary square = (116) (110) = 1/160 mm3

We have 16 secondary squares in each primary square (i.e, square 1, square 2 etc.)

So, total number of secondary squares = (16 4) = 64

Hence, total volume of secondary squares = 64 X (1/160) = 2/5 mm3

Let 'N' be the number of WBCs in 2/5 mm3 of dilated blood.

Then, number of WBCs in 1mm3 of diluted blood = (52) X N

Given, dilution factor = 1/100

Hence, number of WBCs in 1 mm3 of undiluted blood = (5/2) X N X 100 = 250 N (where N = N1 + N2 +N3 + N4)

Slide #1

N = 30 +28 + 25 + 27 = 110

Hence, total number of WBCs in 1mm3 of undiluted blood = 250 X 110 = 27,500

Slide #2

N = 27 + 27+ 24 + 24 = 102

Hence, total number of WBCs in 1mm3 of undiluted blood = 250 X 102 = 25,500