1. Leukocyte Total and Differential Count
Lab 5

2. WBC TOTAL COUNT Can be determined:
manually by haemocytometer and microscope
automated by haematological analysers
by estimation from a blood smear
-100x magnification Mean of 10 fields x 100 = WBC x 109/L
-400x magnification Mean of 10 fields x 1,500 = WBC x 109/L

3. -Leukocyte estimation in a blood smear (400x):
Normal number
Increased
Decreased

4. DIFFERENTIAL LEUKOCYTE COUNT
Can be determined:
from a stained blood smear
automated by some haematological analysers, but these need prior validation

5. DIFFERENTIAL COUNT IN A STAINED BLOOD SMEAR: BATTLESHIP METHOD

6. How to perfom a differential count:
Count leukocytes, note each cellular type identified
Avoid counting the same field twice
Do not focus on one section of the smear

7. TYPES OF LEUKOCYTES GRANULOCYTES: Neutrophils, Eosinophils, Basophils
MONOCYTES
- LYMPHOCYTES

8. Normal neutrophils and a lymphocyte
Neutrophils are similar in most domestic species, characterised by pale cytoplasm and dark nucleus segmented into 2-5 lobes, although granules are more readily seen in ruminants.

9. Small and medium lymphocyte, cow
Small lymphocytes, dog

10. Normal neutrophil and monocyte
Monocytes are similar in most species; large cells with basophilic cytoplasm (often vacuolated or with tiny pink granules), and a pale irregularly clefted or folded nucleus with clumped chromatin.

11. Normal eosinophil and basophil
Morphology of eosinophils varies widely with species; granules are large in horses, small & numerous in ruminants, accompanied by vacuoles in dogs, and rod-shaped in cats.
Basophils have purple-black granules, are numerous in large animals and may be almost absent in healthy dogs and cats.

12. Normal WBCs in different species, some examples
(1)
(2)
Eosinophil
Eosinophil and neutrophil
(3)
Basophil
(4)
Eosinophil and neutrophils

13. REPORTING A DIFFERENTIAL COUNT
By relative % of each WBC type
(INCORRECT)
Ways to
report the
values
By absolute number of each WBC type
(CORRECT)
(%of each cell type x total WBC number)

14. EXAMPLE • Dog nº1 : 70% segmented and 10.0 x 109/L WBCs
% Segmented neutrophils
Absolute segmented neutrophils x 109/L
• Dog nº1 : 70 (NORMAL) NORMAL • Dog nº2: 70 (NORMAL) (DECREASED)
• Dog nº3 : 70 (NORMAL) (INCREASED)

15. INTERPRETING DIFFERENTIAL RESULTS
Neutrophilia
Eosinophilia
Basophilia
Lymphocytosis
Monocytosis
 in a particular leukocyte
Suffix “penia”
(i.e. Lymphopenia)
 in a particular leukocyte