title: Benefit of two-step PPD testing of new employees at a New York City hospital.
abstract: BACKGROUND
  Recent concern about nosocomial transmission of tuberculosis has led hospitals to scrutinize employee tuberculin conversion rates. The Centers for Disease Control and Prevention recommends two-step testing of new employees to limit the booster phenomenon. The cost of such a program and its subsequent yield have not recently been examined.
  
  
  METHODS
  Employee health records were retrospectively reviewed of persons hired from 1993 and 1994 at St. Clare's Hospital in New York City, all of whom received two-step testing at time of initial employment.
  
  
  RESULTS
  Of 262 new employees, 107 (41%) had positive tuberculin results on initial testing. The results of 15 (9.7%) of the remaining 155 patients became positive on two-step testing administered 1 week later. Persons with a positive second test result were significantly more likely to be male or foreign born or to have received previous bacille Calmette-Guérin vaccination. Identification of these 15 persons and exclusion of them from probable subsequent conversion prevented an almost 50% increase in the annual conversion rate at our hospital, from 3.2% to 4.7%.
  
  
  CONCLUSIONS
  Two-step tuberculin testing is an essential means of identifying persons with a baseline positive tuberculin test result, thus allowing accurate reporting of subsequent employee tuberculin conversions.
authors.affiliation: St. Clare's Hospital and Health Center, New York, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Sepkowitz
authors.forename: J
authors.initials: J
authors.lastname: Feldman
authors.forename: J
authors.initials: J
authors.lastname: Louther
authors.forename: P
authors.initials: P
authors.lastname: Rivera
authors.forename: N
authors.initials: N
authors.lastname: Villa
authors.forename: J
authors.initials: J
authors.lastname: DeHovitz
mesh_terms: D000328:Adult; D001500:BCG Vaccine; D002487:Centers for Disease Control and Prevention, U.S.; D003428:Cross Infection / Q000517:prevention & control*; D004651:Employment; D005260:Female; D017408:Guidelines as Topic; D006744:Hospital Bed Capacity, 100 to 299; D006801:Humans; D008297:Male; D009163:Mycobacterium bovis / Q000472:pathogenicity; D009169:Mycobacterium tuberculosis / Q000472:pathogenicity; D009519:New York City; D010564:Personnel, Hospital / Q000592:standards*; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000517:prevention & control* / Q000635:transmission; D014481:United States
chemical_list: D001500:BCG Vaccine