This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
False positive ELISA for HIV - 
Select and explain. 
A. Multiple mycloma, B. Lepromatous leprosy, C. SLE, D. All of the above
C: SLE
Answer: C: SLE 
Explanation: 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