You can buy secondary antibodies that are already conjugated to various reagents to allow detection, such as fluorescent dyes, biotin, alkaline phosphatase and horseradish peroxidase. You can also buy protein A and protein G conjugates to bind to certain immunoglobulin subtypes.

Thank you so much for your input Adam, but when we try to build a multiplex panel, I think being able to conjugate secondary and have whatever fluophore we wish for in order for various antibodies to be incubated on the tissue would be more convenient and cost effective. Correct me if I am wrong or if I am missing the point. Again I am new to this so just trying to weigh all my options. Thank you once again!

I am not sure if I misunderstand your response to Adam, but if you want to do multiplexing then the use of secondary antibodies can be quite tricky, especially if you have more than two or three primary antibodies. They would have to be from different species and your secondaries would have to be completely specific for the intended target.

If you really do mean multiplexing (i.e. using several different primary antibodies simultaneously) then you do need to label them first, each with a different label. The advantage here is that you can have any combination of species or all primary Abs from one species.

If you mean that you have a lot of antibodies that will be used individually in a large experiment, then you could simply buy secondaries with different labels as Adam says. There is nothing to stop you from making your own labeled secondaries of course, but this is quite unusual and most people would just buy them ready made.