Screening For Tb or a positive TB skin test or TB blood test only tells that a person has been infected with TB bacteria. It does not tell whether the person has latent TB infection (LTBI) or has progressed to TB disease. Other tests, such as a chest x-ray and a sample of sputum, are needed to see whether the person has TB disease. The essential screening technique for TB disease (dynamic or inactive) is the Mantoux tuberculin skin test with decontaminated protein subsidiary (PPD). An in vitro blood test dependent on interferon-gamma discharge test (IGRA) with antigens explicit for M tuberculosis can likewise be utilized to screen for dormant TB disease.