Page 318 - The Veterinary Laboratory and Field Manual 3rd Edition

Haematology 287

(a)

(b)

Figure 5.4 (a) Filling the counting chamber using a Pasteur pipette. (b) Improved Neubauer ruling for
a blood counting chamber. All dimensions are in millimetres. The central portion of the square is also
illustrated.

Calculation (depends on the type of If N = 240 the TWCC = 12,000/µl = 12.0
haemocytometer used)
× 10 /µl = 12.0 × 10 /ml = 12.0 × 10 /l
6
3
9
Total number of cells counted = N (for

example, 240); volume = 4 mm (area
2
counted) × 0.1 mm (depth of chamber) = Total red cell count
0.4 mm; dilution = 1/20 PrEParE tHE dILutInG FLuId
White cells per microlitre = N × 1/0.4 × Dilute fluid: formol-citrate 1% in 3% aque-
20 = N × 50 ous trisodium citrate. 4

Vet Lab.indb 287 26/03/2019 10:25