- Whole blood (EDTA ) is needed.
- Heparinized blood can also be used.
- The absolute count should be done within 4 hours or refrigerate the sample but do count within 24 hours.
- Eosinophils count is done to diagnose allergic conditions.
- To diagnose parasite infestation and its severity.
- This can be used to monitor the treatment of parasites.
- The eosinophils develop from the stem cells in bone marrow.
- Myeloid series cells get maturation under the influence of granulocytes colony-stimulating factor (G-CSF).
- Eosinophils are like neutrophils except the cytoplasm contains orange or red staining granules.
- The blood transient time for the eosinophils is longer than the neutrophils.
- There is a diurnal variation of eosinophils count.
- the lowest count will be in the morning, 10 AM to 12 AM and highest level at midnight (4 am).
- The eosinophils can act as phagocytic cells.
- Eosinophils are active in antigen-antibody complexes.
- Eosinophils are rich in histamine granules.
- Eosinophils take part in hypersensitivity reaction type 1.
- Eosinophils with the help of antibody IgE can produce histamine from the mast cells or the basophils.
- Eosinophils functions:
- It is detoxification.
- A special role in the allergic reaction.
- They are defensive against the parasitic infestation.
- Eosinophils remove the fibrin during the inflammation,
- If the eosinophils count is raised >1.5 X 10×9 /L for more than 6 months and associated with tissue damage. is diagnosed with the hypereosinophilic syndrome.
Typical eosinophil with prominent eosinophilic granules.
Procedure to count Eosinophils:
1. The best method to count eosinophils is the automated analyzer.
2. Dunger's solution:
- This will use the acid dye like eosin.
- Water may be used to lyse the RBC when the eosinophils are resistant to water.
3. Phloxine stain: It consists of:
- Phloxine 0.1% solution to water 10 mL.
- Distilled water 40 mL.
- Propylene glycol 50 mL.
- Sodium carbonate 1% 1 mL.
- A sample of the blood is diluted in the WBC pipette as 1: 20 dilution with staining fluids.
- Mix well for 30 seconds.
- Now fill the chamber and count the colored eosinophils.
- Leave the chamber for at least 10 minutes to count the cells.
- Absolute value : 50 to 400 cell/cmm
- Peripheral blood smear (DLC): 1 to 5%
- Absolute count = 0 to 0.7 x 109/L
- Differential count = 0 to 3% of total WBC
Eosinophilia, Increased Eosinophil count is seen in:
- when eosinophils are more than 5 % or > 500 cells/cmm.
- Allergic disorders.
- Bronchial asthma.
- Angioneurotic edema.
- Hay fever.
- Drug sensitivity.
- Skin diseases.
- Exfoliative dermatitis.
- Parasitic infestations
- Especially those parasites which invade the tissue. e.g. Trichinosis, and Echinococcus.
- Hematological disorders.
- Chronic myeloid leukemia.
- Polycythemia vera.
- Pernicious anemia.
- Hodgkin's lymphoma.
- Hypereosinophilic syndrome.
- Eosinophilic leukemia.
- Trichinosis invasion.
- Dermatitis herpetiformis.
- Malignant tumors, especially with metastasis and necrosis.
- Loeffler’s syndrome.
- Tropical eosinophilia.
- Rheumatoid arthritis.
- Certain poison.
Eosinopenia, when < 50/cmm seen in the following conditions:
- Cushing’s syndrome.
- Due to some drugs like ACTH, epinephrine, thyroxine, and prostaglandin.
- In the shift to the left where there are immature cells.
Possible References Used
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