An in vitro method of detecting an infection with pathogens causing tuberculosis comprising the steps: a) contacting a first aliquot of a sample of an individual with at least one antigen of a pathogen causing tuberculosis, in particular wherein a heterodimer of two antigens, more preferably a heterodimer of ESAT-6 and CFP-10, is added to the first aliquot or wherein the first aliquot is comprised in a container comprising a heterodimer; b) incubating the first aliquot with the at least one antigen for about 15 to about 23 hours, c) adding a cell lysing reagent which is able to stabilize RNA in a temperature range of about 0°C to about 40°C, more preferably of about 2°C to about 30°C, or of about 15°C to about 30°C, or of about 2°C to about 8°C, or of about 15°C to about 25°C, or about of 18°C to about 30°C for about 2 h to about 48 h, more preferably for about 12 h to about 48 h more preferably for about 2 h to about 72h, more preferably for about 12 h to about 72h, d) performing an RNA extraction from the mixture obtained in step c), preferably an automated RNA extraction, wherein RNA is extracted from the mixture obtained in step c) without any prior washing or separation steps; e) detecting in the first aliquot and in a second aliquot of the sample of the individual the markers IFNG and CXCL10 and at least one housekeeping gene using a 1-step or 2-step reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), wherein the second aliquot has not been incubated or stimulated with the at least one antigen, and f) comparing all of the detected markers in the first aliquot with the detected markers in the second aliquot, preferably in a fold change analysis, more preferably in a classifier method, wherein the sample of the individual in step a) is whole blood, in particular anti-coagulated whole blood, or a purified or isolated PBMC population, lymph or a bronchial lavage and wherein the cell lysing reagent which is able to stabilize RNA comprises a detergens such as such as Triton X 100, Tween 20, Tween 80, 3 [(3 Cholamidopropyl)dimethylammonio] 1 propanesulfonate (CHAPS), urea and/or n-Dodecyl-β-D-Maltopyranoside, a chaotropic agent such as a guanidinium lysis buffers comprising preferably guanidinium isothiocyanate and/or guanidinium-HCl and an antioxidant such as DTT, Dithioerythritol, Tris(2-carboxyethyl)phosphin (TCEP) and/or β-Mercaptoethanolopic agent. a) contacting a first aliquot of a sample of an individual with at least one antigen of a pathogen causing tuberculosis, in particular wherein a heterodimer of two antigens, more preferably a heterodimer of ESAT-6 and CFP-10, is added to the first aliquot or wherein the first aliquot is comprised in a container comprising a heterodimer; b) incubating the first aliquot with the at least one antigen for about 15 to about 23 hours, c) adding a cell lysing reagent which is able to stabilize RNA in a temperature range of about 0°C to about 40°C, more preferably of about 2°C to about 30°C, or of about 15°C to about 30°C, or of about 2°C to about 8°C, or of about 15°C to about 25°C, or about of 18°C to about 30°C for about 2 h to about 48 h, more preferably for about 12 h to about 48 h more preferably for about 2 h to about 72h, more preferably for about 12 h to about 72h, d) performing an RNA extraction from the mixture obtained in step c), preferably an automated RNA extraction, wherein RNA is extracted from the mixture obtained in step c) without any prior washing or separation steps; e) detecting in the first aliquot and in a second aliquot of the sample of the individual the markers IFNG and CXCL10 and at least one housekeeping gene using a 1-step or 2-step reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), wherein the second aliquot has not been incubated or stimulated with the at least one antigen, and f) comparing all of the detected markers in the first aliquot with the detected markers in the second aliquot, preferably in a fold change analysis, more preferably in a classifier method,