State the principle on which ELISA technique is based . How does it help in early detection of a disease

Anenzyme-linked immunosorbent assay, also called ELISA or EIA, is a test that detects and measures antibodies in your blood. This test can be used to determine if you have antibodies related to certain infectious conditions. Antibodies are proteins that your body produces in response to harmful substances calledantigens.

An ELISA test may be used to diagnose:

• HIV, which causes AIDS
• Lyme disease
• pernicious anemia
• Rocky Mountain spotted fever
• rotavirus
• squamous cell carcinoma
• syphilis
• toxoplasmosis
• varicella-zoster virus, which causeschickenpoxandshingles
• Zika virus

ELISA is often used as a screening tool before more in-depth tests are ordered. A doctor may suggest this test if you’re having signs or symptoms of the conditions above. Your doctor may also order this test if they want to rule out any of these conditions.