Health care workers (HCW) are particularly at risk of acquiring tuberculosis 
(TB), even in countries with low TB incidence. Therefore, TB screening in HCW is 
a useful prevention strategy in countries with both low and high TB incidence. 
Tuberculin skin test (TST) is widely used although it suffers of low 
specificity; on the contrary, the in vitro enzyme immunoassay tests (IGRA) show 
superior specificity and sensitivity but are more expensive. The present study 
reports the results of a three-year TB surveillance among HCW in a large 
teaching hospital in Rome, using TST (by standard Mantoux technique) and IGRA 
(by QuantiFERON-TB) as first- and second-level screening tests, respectively. 
Out of 2290 HCW enrolled, 141 (6.1%) had a positive TST; among them, 99 (70.2%) 
underwent the IGRA and 16 tested positive (16.1%). The frequency of HCW tested 
positive for TB seems not far from other experiences in low incidence countries. 
Our results confirm the higher specificity of IGRA, but, due to its higher cost, 
TST can be considered a good first level screening test, whose positive results 
should be further confirmed by IGRA before the patients undergo X-ray diagnosis 
and/or chemotherapy.