[Importance of molecular methodology in diagnosis]

The National Institute for Epidemiological Diagnosis and Reference (INDRE) partially supports epidemiological surveillance programs through the identification of most infectious agents prevalent in the country. The success of a program for the control or eradication of a particular infectious disease mainly depends on the opportune and accurate identification of the corresponding etiologic agent. For laboratory diagnosis at INDRE, both conventional methodology using direct or microscopic examinations of specimens or growth in culture media followed by physiological or immunological characterization of the isolate, as well as new techniques based in biochemical, immunochemical and molecular biology procedures are carried out. Antigens can be detected in clinical samples by ELISAs with polyclonal or monoclonal antibodies. Specific nucleic acids can be extracted, identified and typed with techniques like electrophoresis, hybridization with genomic probes, polymerase chain reaction or fragment restriction length polymorphism. Recombinant molecules or highly purified antigens are being obtained and used for the determination of antibodies, mainly with indirect ELISA, IgM capture-ELISA and Western Blot. The better performance, specificity and sensitivity of these laboratory procedures, provide faster results, with equal or greater accuracy than traditional ones, at lower cost.