This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
[{'content': 'Diagnosis of Dengue fever can be made earliest by- \nSelect and explain. \nA. Viral culture, B. NS - 1 antigen detection, C. IgG antibody detection, D. Nucleic acid test', 'role': 'user'}, {'content': "Answer: B \nExplanation: 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", 'role': 'assistant'}]