The present invention discloses the use of Mycobacterium tuberculosisantigens for use in in vivodetermination of the presence of Mtbinfection in immunocompromised persons or persons co-infected with HIVand the for preparing a diagnostic reagent for skin testing (a skin test reagent) for robust assessment of the presence of Mtbinfection in an individual wherein the individual is an immunocompromised person or a person co-infected with HIV.