agglutination and precipitation - when we can use agglutination and precipitation fo (Jul/03/2005 )

Dear friends...
I think its very basic question .....

when we can use agglutination and precipitation for diagnosis ...and why? Its have any molecular level explanation plz someone explain me....

Thankyou


Rojaa

agglutination rxs such as slide tests for hCG, etc.

precipitation rxs such as precipitation lines in RID for identifying Ig classes