Precipitation Tests Involve All of the Following Except

Multiple Choice

Precipitation tests involve all of the following except

A) a cloudy or opaque zone developing where antigen and antibody react.
B) they rely on formation of visible clumps for detection.
C) they can be done in a test tube by carefully adding antiserum over antigen solution.
D) they include the VDRL test for syphilis.
E) they are often performed in agar gels.