WBC manual count using hemocytometer

Introduction WBCs count is the count of leukocytes in a volume of blood Expressed as WBCs/mm³

Material Blood sample (EDTA anticoagulated blood or capillary blood) WBCs diluting pipette Diluting solution Hemocytometer microscope

The Hemacytometer contains 2 Neubauer counting chamber Each chamber contains: *4 WBC counting squares *Each contains 16 squares

Methodology draw blood up to 0.5 marks on WBCs pipette and complete to 11 with WBCs diluting solution(Turk‘s solution). Mix for 2-3 minute.

Turk's solution Türk's solution is a composed of a stain (Gentian violet) and 1-2% acetic acid. The solution destroys red blood cells within a blood sample, and stains the nuclei of the white blood cells, making them easier to see and count. Turk's Solution is intended for use in counting leukocytes in a defined volume of blood. Erythrocytes are hemolyzed while leukocytes are stained for easy visualization. Dr.Sajeda Al-Chalaby

Charge hemacytometer Discard the first 4-5 drops Place tip of the pipette at the edge central platform Then let the hemacytometer to stand on the bench for 3-5 minute.

Count and calculate:

Turk's solution Türk's solution is a composed of a stain (Gentian violet) and 1-2% acetic acid. The solution destroys red blood cells within a blood sample, and stains the nuclei of the white blood cells, making them easier to see and count. Turk's Solution is intended for use in counting leukocytes in a defined volume of blood. Erythrocytes are hemolyzed while leukocytes are stained for easy visualization. Dr.Sajeda Al-Chalaby

Calculation Number of cells/mm³= counted cells in 4 large square/ 4 x diluting factor x volume correction factor.

Calculation The dilution factor= total volume/sample volume = 11-1/0.5 =20

Calculation counted volume = The total volume of the 1 large square= = (width x length x depth ) = (1mm x 1mm x 1/10 mm) =1/10

Calculation Number of cells/mm³= counted cells in 1 large square x diluting factor x volume correction factor. Number of cells/mm³= n x20 x 10 = n x 200

Example: If total number of WBCs in 4 squares is 120 Then the number of WBCs in 1mm³= 120/ 4 x 200 =6000

Normal values of WBCs: Newborn 9000-30000 cell/mm³ Adult 4000-11000 cell/mm³ Neutrophil 62% Eosinophil 2.3% Basophil 0.4% Monocytes 5.3% Lymphocyte 30%

Significance of the test Leukocytosis Occur as an indicator of body defense against foreign materials (bacteria, parasites, toxins) Metabolic disorders Chemical and drug poisoning Acute hemorrhage

Significance of the test Leukopenia Result from X-ray therapy Alcoholism Antibiotic therapy Typhoid infection Measls Infectious hepatitis TB And cirrhosis of the liver

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