... purposes)Journal of Occupational Medicine and ToxicologyOpen AccessResearch In-hospital contact investigation among health care workers after exposure to smear-negative tuberculosisFelix C Ringshausen*1,2, ... A, Nienhaus A, Schultze-Werninghaus G, Rohde G: Contact tracing with an interferon-gamma release assay in health care workers after exposure to smear-negative, culture-positive pulmonary tuberculosis[abstract]. ... low-incidence, in-hospital setting, is limited. We conducted a large-scale, in-hospital contact investigation among HCW of a German university hospital after exposure to a single case ofextensive smear-negative, ...