[1] Titer testing employs serial dilution to obtain approximate quantitative information from an analytical procedure that inherently only evaluates as positive or negative.
It is conventionally expressed as the inverse of the greatest dilution level that still gives a positive result on some test.
For example, the indirect Coombs test detects the presence of anti-Rh antibodies in a pregnant woman's blood serum.
Many traditional serological tests such as hemagglutination or complement fixation employ this principle.
Such tests can typically be read visually, which makes them fast, cost-effective, and able to be deployed in a wide variety of laboratory environments.