The antibodies picked must have a high affinity for the antigen (if there is antigen available, a very high proportion of it must bind to the antibody).Antigen is also a deciding factor.
yepOriginally posted by ndmmxiaomayi:Hmm...
Antigen is also a deciding factor.
Should be quite accurate, assuming that the serum or urine doesn't have other antigens that attract the same antibodies as well...