title: Screening for tuberculosis and prediction of disease in Portuguese healthcare workers.
abstract: BACKGROUND
  Results of systematic screening of healthcare workers (HCWs) for tuberculosis (TB) with the tuberculin skin test (TST) and interferon-γ release assays (IGRA) in a Portuguese hospital from 2007 to 2010 are reported.
  
  
  METHODS
  All HCWs are offered screening for TB. Screening is repeated depending on risk assessment. TST and QuantiFERON Gold In-Tube (QFT) are used simultaneously. X-ray is performed when TST is > 10 mm, IGRA is positive or typical symptoms exist.
  
  
  RESULTS
  The cohort comprises 2,889 HCWs. TST and IGRA were positive in 29.5%, TST-positive but IGRA-negative results were apparent in 43.4%. Active TB was diagnosed in twelve HCWs - eight cases were detected during screening and four cases were predicted by IGRA as well as by TST. However, the progression rate in IGRA-positive was higher than in TST-positive HCWs (0.4% vs. 0.2%, p-value 0.06).
  
  
  CONCLUSIONS
  The TB burden in this cohort was high (129.8 per 100,000 HCWs). However, the progression to active TB after a positive TST or positive IGRA was considerably lower than that reported in literature for close contacts in low-incidence countries. This may indicate that old LTBI prevails in these HCWs.
authors.affiliation: University Medical Centre Hamburg-Eppendorf, Institute for Health Services Research in Dermatology and Nursing, Hamburg, Germany. a.nienhaus@uke.uni-hamburg.de.
authors.forename: José
authors.initials: J
authors.lastname: Torres Costa
authors.forename: Rui
authors.initials: R
authors.lastname: Silva
authors.forename: Felix C
authors.initials: FC
authors.lastname: Ringshausen
authors.forename: Albert
authors.initials: A
authors.lastname: Nienhaus