ABSOLUTE EOSINOPHIL COUNT.

EOSINOPHIL

• Eosinophil are specialized white blood cell that are also known as biolobed cell.
• Eosinophil have two lobed nucleus and coarse (larger) granules in the cytoplasm.
• It pick up acidic stain (Eosin) and stain pick or red in color.
• Diameter of the cell varies between 10 to 14u.

ABSOLUTE EOSINOPHIL COUNT.

• An absolute eosinophil count is a blood test that measure the number of Eosinophil.
• This test also helpful to diagnosis of allergic disease, Asthma, drug reaction, parasitic infection and other medical condition.

METHOD OF ABSOLUTE EOSINOPHIL COUNT

An absolute Eosinophil count are done by two method.

1. Indirect method.
2. Direct method.

1. INDIRECT METHOD

In the indirect method we are use a methematical formula for get absolute number of Eosinophil.

AEC = % of Eosinophil from DLC × TLC

                                   100

For example:-

If a person TLC count is 6300 and Eosinophil percentage in DLC is about 3%.

AEC = % of Eosinophil from DLC × TLC

                                   100

  = 3 × 6300. 

         100                = 189/mm3

 2 .DIRECT METHOD

• The direct method is quick and give exact value of Eosinophil.
• In this method we diluted blood with a diluting fluid (dunger)
• Then charged in the counting chamber and the number of Eosinophil are counted usually under 10x and 40x.

PRINCIPLE 

Blood is diluted with special diluting fluid which stain the eosinophilic granules brightly and distinctly at tha same time tlit lyses the RBC and other WBC.

REQUIREMENTS

• Eosinophil diluting fluid.
• Hemocytometer.
• Blood sample.
• Cover slip.
• Microscope.
• Pipette.

HEMOCYTOMETER 

• For absolute Eosinophil count , Fuchs Rosenthal chamber is commonly used.
• The chamber has ruled are 16 sq mm and the depth is 0.2mm.
• It occupies more amount of fluid compared with other counting chamber.
• Their square are orientated by triple line and each area sub divided in 16 square.

EOSINOPHIL DILUTING FLUID

Dunger fluid are use for Eosinophil dilution. Dunger fluid are composed by :-

1. Eosin 1% solution=     5ml
2. Acetone = 5ml 
3. Distilled water = 100ml

PROCEDURE

1. Take 950 ul diluting fluid in a clean, dry test tube.
2. Add 50 ul anticoagulant blood sample and mix.
3. Keep for 5 min at room temperature.
4. Mix and fill the chamber with the help of pipette.
5. Allow it to settle for few minutes.
6. Then observer under microscope.

CALCULATION

AEC  = No of cell counted × diluting factor 

                         Area × depth

There.  N= number of cell counted

             Dilution factor = 10

             Area  = 16

             Depth= 0.2mm

So Eosinophil count = N × 3.12

NORMAL VALUE

50 to 300 cells per cubic mm.

CLINICAL SIGNIFICANCE

Decrease :- rare and medically insignificant.

Increase:-  asthma , allergic ,drug reaction, parasitic infection.

PRECAUTION

• Always Clean the chamber before and after use.
• After taking blood in pipette clean the outer surface of tip before diluting it in the diluting fluid.
• Always mix the dilution before filing the chamber.
• Avoid bubble to come in the chamber.
• Never over flow the chamber with dilution.
• For Decrease the error more cells must be count.
• Change the cover glass if dirty and scratched.
• Clean the microscope before and after every use.