OBJECTIVES: We sought to define the prevalence of tuberculin skin test
(TST) positivity in a group of newly hospitalized patients, to identi
fy risk factors for positive tests, and to examine the impact of testi
ng on infection control practices. DESIGN: Unblinded cohort study over
5 days in July 1992. SELLING: A 1,000-bed university-affiliated hospi
tal. PATIENTS: All patients admitted (excluding obstetric patients and
newborns) were interviewed. Patients without a history of tuberculosi
s (TB) or a positive TST were offered a TST with Candida and tetanus c
ontrols. RESULTS: Of 346 patients offered the test, 21 (6%) had a prio
r history of TB or a positive TST, and 36 (10%) declined to participat
e; 279 of the remaining 289 completed the study. Anergy was demonstrat
ed in 94 (33.7%) of 279 patients. New positive TSTs were identified in
19 (10.3%) of 185 nonanergic patients. Of the 19 TST-positive patient
s, 6 (32%) had infiltrates on chest radiographs and were evaluated for
active TB. One patient was treated empirically for active TB, and fiv
e received isoniazid prophylaxis. Risk factors for a new positive TST
included age (odds ratio [OR], 1.56 per decade of life; P=.021), Afric
an American race (OR, 4.81; P=.008), alcohol abuse (OR, 5.53; P=.005),
and peptic ulcer disease (OR, 4.53; P=.017). Risk factors for anergy
included admission to a surgical service (OR 2.1; P=.006), current use
of steroids (OR, 2.65; P=.005), and human immunodeficiency virus (HIV
) infection (OR undefined; P=.034).CONCLUSIONS: Despite a high rate of
anergy, routine tuberculin skin testing identified a substantial numb
er of patients with TB infection who might otherwise have gone unrecog
nized (Infect Control Hosp Epidemiol 1997;18:561-565).