fixation process with formalin probably denatures/destroys the item of
interest thereby changing the epitopes available for the antibodies to
see/bind . Especially a problem with a monoclonal antibody based assay
since it would see only 1 epitope. Depending upon the monoclonal used the
effect could mean no reactivity to no problem at all (if the epitope of
interest is not effected). You may need to try someone else's assay to see
if the effect is still seen. Adjusting the percentage of formalin (lower)
may also allow greater reactivity.
Sincerely,
Bret G Wien
Research Diagnostics Inc
