Definition:
The amount or concentration of a substance in solution. The term is often used to described concentrations of biological molecules (bioproducts) such as antibodies and other proteins. The titer is an indication of the number of times the solution can be diluted and still contain detectable amounts of the molecule of interest. In fact, when calculating titer, the numerical value assigned to a titer is directly indicative of the dilution factor.
Examples:
The doctor was concerned with the patient's low antibody titer of 32, since a value of 8 was normal.