ABSOLUTE EOSINOPHIL COUNT

• 40 – 440 per µl of blood

• Differential count of leucocytes yields the relative number of eosinophils in the leucocyte population. It is possible to find the absolute number of eosinophils in circulation by performing direct and indirect absolute counts.
• Eosinophils usually have bilobed nuclei. In a stained preparation, the granule take on a deep red or brick-red colour. In absolute count, other leucocytes and red cells are destroyed:making it easy to distinguish Eosinophils.
• Eosinophils are present in large numbers in parasitic infestations in which they appear to serve an important defence function. In allergic conditions, Eosinophil dampens the host’s response by limiting the antigen induced release of mediators of inflammation.
• Eosinophils are phagocytic and destroy organisms through oxidative mechanisms similar but not identical to those of neutrophils. It can phagocytose bacteria, fungi and inert particles, but are less efficient than neutrophils.
• The number of Eosinophils in the blood alters significantly in different allergic diseases and parasitic infestations. The Eosinophil count is also taken as an index of ACTH activity in the blood. If ACTH is injected intramuscularly in a subject with normal adreno cortical function, it results in the reduction of total number of circulating Eosinophils. This effect has been used as a test of adrenocortical function. This is called the Thorn test. It is not a specific test and the value of the test is limited.

• When there is s/s such as itchy eyes, nasal congestion, asthma , dermatitis, which may suggest an allergy to one or more substances
• In case of Parasitic infections
• When there is an abnormally high or low count of WBCs
• To diagnose hypereosinophilic syndrome

Elevated level (Eosinophilia)

Allergic diseases

• Bronchial asthma
• Hay fever
• Food allergy

Parasitic infestations

• Hook worm
• Round worm
• Tape worm
• Filaria

Skin diseases

• Eczema
• Pemphigus
• Dermatitis herpetiformis

Tropical pulmonary eosinophilia and Loeffler’s syndrome

Malignant neoplasia

• Eosinophilic leukemia
• Lymphoproliferative disorders e.g. Hodgkins disease
• Secondary carcinomas

Addison’s disease

Decreased Level (Eosinopenia)

• Cushing syndrome
• Aplastic anemia
• ACTH therapy