Diagnosis of Dengue fever can be made earliest by-

Ans. is 'b' i.e., NS-1 antigen detection Dengue diagnostics and sample characteristics Clinical sampleDiagnostic methodMethodologTime to result Viral isolationMosquito or mosquito cell culture inoculationOne week or moreVirusDetectionand itscomponentsAcute Serum(1-5 days of fever)andnecropsy tissues Nucleic acid detectionRT-PCR and real time RT-PCR1 or 2 days NS1 Ag rapid testsMinutes Antigen detectionNS I Ag ELISA1 day I mmuno-histochemistry2-5 days Paired sera (acute serum from 1-5 days and second serum 15-21 days after)IgM or IgG seroconversionELISAHIA1-2 daysSerologicalresponseNeutralization testMinimum 7 days IgM detection(recent infection)ELBA1 or 2 daysSerum after day 5 of feverRapid testsMinutesIgG detectionIgG ELISAHIA1 or 2 days