Classical Methods for Diagnosis - The infectious diseases such as STD are diagnosed usually by any one of the following four classical methods (these methods do not involve biotechnology).

(i) Microscopic examination of tissue specimens and exudates for identification of virus infected cells, bacteria, fungi or other parasites.
(ii) Culture methods with selective growth media permitting multiplication of some microorganisms, which can then be tested for susceptibility to potential therapeutic agents.
(iii) Immunological methods where antigens associated with specific pathogens are identified in tissue or body fluids.
(iv)Measurement of antibody produced in the patient as a result of infection with an organism.