The optimal antibody titer is that greatest dilution that still generates the maximum signal to noise ratio.In other words, antibody titer is a measurement of how much of the specific antibody the mouse/hybridoma has produced against a single epitope on your antigen, expressed as the greatest dilution ratio (or its reciprocal) that still gives a positive result. There are different methods available and the most commonly used method is the ELISA and it is our method of choice too.