<prompt> A patient presented with cough and evening rise of temperature since one month. Which among the following is the definitive diagnostic test for tuberculosis?Grams stainingCultureGuinea-pig inoculationTuberculin testing  <response>: Definitive diagnosis depends on the isolation and identification of M. tuberculosis from a clinical specimen or the identification of specific sequences of DNA in a nucleic acid amplification test. Specimens may be inoculated onto egg- or agar-based medium e.g., Lowenstein-Jensen or Middlebrook 7H10 and incubated at 37degC under 5 CO2 for Middlebrook medium. Because most species of mycobacteria, including M. tuberculosis, grow slowly, 4-8 weeks may be required before growth is detected. Ref: Raviglione M.C., OBrien R.J. 2012. Chapter 165. Tuberculosis. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo Eds, Harrisons Principles of Internal Medicine, 18e. 