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What is False positive ELISA for HIV - and explain in detail?
False positive ELISA is seen in -

Antibodies to class II antigens - Recent influenza vaccination
Auto antibo dies  - Acute viral infections
Hepatic disease  - Connective tissue diseases e.g. SLE.
ELISA is the standard screening test for HIV infection
It has a sensitivity of > 99.5%, while it is highly sensitive, it is not optimal in regard to specificity.
Most commonly used confirmatory test for the diagnosis of HIV infection - a Western Blot test