1when it comes to cell counting in the clinical setting inorder to aid the diagnosis of ailments it will be proper to mention its history how it was developed before we talk about how it is used.The haemocytometer as it is called is a piece of thick glass with ruled areas to count the number of various peripheral blood cells like erthrocytes (red blood cells),leucocytes (white blood cells),thrombocytes (platelets) which was develped by a french anatomist and histologist  Dr.Loius-charles Malassez (1842-1909) see figure 1 who studied medicine in paris and in 1875 attained the chair of anatomy at  college of france and was a member of the academy of medicine.

The fungus genus of malassezia and epithelial cell rests of malassez (ERM) in the field of mycology and dentistry hold his name as eponyms.Haemopoiesis is a term used to define blood cell production by the body haemopoietic stem cells are capable of differentiating into the various peripheral blood cells we sees on a blood film.

Generally haemopoietic stem cells differentiate into five blast cells (nucleated precursor cells) and these are:-1-proerythroblasts which form erthytrocytes.

2-Myeloblasts which form mature neutrophils,eosinophils,and basophils.

3-Monoblasts which form mature monocytes.

4-Lymphoblasts which form mature lymphocytes.

5-Megakaryoblasts which form mature platelets.

Haemopoiesis takes place  in the red bone marrow which is found in the epiphyses or ends of long bones such as the humerus and femur.In addition to the sternum,ribs,cranial bones,the vertebrae and the pelvis.Certain haemopoietic growth factors stimulate differentiation and proliferation of certain proginator cells for instance Thrombopoietin is a hormone that stimulate  platelet formation.

Colony-stimulating factor  and interleukins are cytokines which stimulate white blood cell or leucocyte formation.The counting chamber called Neubaeur counting chamber is a thick glass with 4 protruding shoulders and two counting ruled ares with 3mm2 area with a depth of 0.1 mm.

The ruled area is where the RBC,WBC and platelet are counted the area of 1,2,3,and 4 for wbc and the central A,B,C,and D for rbc and platelet count. see figure 22

RBC  count

when counting rbc per mm3 we use a tomma pippette with red bead in it with a mark 101.

Diluting fluid

formal citrate1%

Formula

Total rbc counted x 50 x 200

WBC count

when counting wbc we use the white bead tomma pippette with 11 mark.

Diluting fluid

acetic acid 2%

Formula

Total wbc cells counted x 2.5x 20

Reference ranges source:- Oxford medical dictionary

RBC:-4.5×6.5×10 12/L or 4,500,000-6,500,000 /uL

WBC:-4.0×11.0x10 9/L or 4,000-11,000/uL

neutrophil:-2.0 – 7.5×10 9/L or 2000-7000/uL

Lymphoctes:-1.3-3.5 x 10 9/L or 1,300-3,500/uL

eosinophils:- 0-0.44 x10 9/L or 0-440 /uL

Basophils:-0 – 0.10 9/L or 0-100 /uL

monocytes 0.2-0.8 X 10 9 /L or 200 – 800 /uL

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