The delayed diagnosis of tuberculosis in our patients may be due to the multifaceted clinical presentation of the disease and to the decreasing familiarity of physicians with this infection in Germany. TB in native patients of German origin most frequently present as pulmonary TB in elderly, debilitated patients . This is one of the reasons why the TB control in Germany after World War II based on mass chest-X-ray screening was successful. Moreover, the delayed diagnosis may be partly due to the particular characteristics of the selected patient collective observed, i.e. HlV-negative immigrants which is not representative for all TB patients notified. For instance, in 2009 in Düsseldorf 60 new cases (31 male/29 female; 32% German, 68% immigrants or foreigners) have been notified. Among these, 72% had pulmonary involvement, 28% were exclusively extrapulmonary. In our cohort, most patients were female and young and had neither respiratory complaints nor B symptoms. In tropical regions, exclusively extrapulmonary presentation of TB is relatively frequent, a notion confirmed by our cohort [2, 4, 5]. Furthermore, TB is usually deemed to increase inflammatory parameters such as ESR, or CRP. These are not only non-specific, but surprisingly, a number of patients even with disseminated TB had normal ESR and/or CRP. The most sensitive parameter would have been an abnormal protein electrophoresis. Nowadays TB-IGRA's are preferred to TST because the IGRA's are more sensitive and more specific than TST [6–11]. Especially, TB-IGRA's although also covering M. bovis are not confounded by previous BGG vaccination . In particular, for the patient collective described, we do not share the opinion that TST is obsolete: firstly, at least in adult immigrants from countries with high TB incidence a positive TB-IGRA does not enable to differentiate between latent inactive and active TB. If we assume that the more than 2 billion TB cases worldwide most frequently occur in high incidence countries, a positive IGRA may be expected in more than one third of people from high incidence countries at least from adolescence on . Secondly, although the TST is usually less sensitive and less specific than TB-IGRA, in our cohort false negative results did not occur. Thirdly, and most importantly, contrary to TB-IGRA, skin reaction to tuberculin can be semi-quantified into weakly to strongly positive. So far, for TB-IGRA, there is no quantitative assessment which would prove active TB . on the other hand, in our patients without overt immuno-incompetence suspicion of TB mostly aroused by the intensity of their skin reaction to tuberculin. This is why, for the moment, we see both tests as complementary tools rather than as mutually exclusive. In future, TB-IGRA may be useful for the diagnosis of active TB when applied to body materials other than blood, e.g. bonchoalveolar lavage, cerebrospinal fluid, pericardial, pleural or peritoneal effusions [13–17]. Performance of PCR for nucleic acids of M. tuberculosis was unsatisfactory. Sensitivity of PCR as compared to culture was lower than 50%. PCR did not perform better in its licensed application on respiratory materials than in its application on other materials. However, a positive PCR was very helpful for speeding up the diagnostic progress and initiation of therapy because of the rather long time interval a TB culture takes to become positive.