SCREENING HIGH-RISK populations for tuberculosis (TB) and treating those with infection has been shown to be a cost-beneficial component of a comprehensive TB elimination strategy.1 For children living in areas with a high prevalence of TB, screening is recommended2 at ages 4 to 6 years and 11 to 16 years. Children with risk factors, such as recent immigration, institutional residence, incarceration, or exposure to adults at high risk for TB, should be tested with greater frequency.2 Unfortunately, many children, especially adolescents, do not receive routine medical care, which makes such screening possible. Even if patients are seen for routine health maintenance, skin tests can be problematic, because a return visit is needed to read the test results. The current recommendation of the American Academy of Pediatrics3 is to treat children and adolescents with positive tuberculin skin test (TST) results and no evidence of clinical disease with isoniazid. Unfortunately, even when appropriately prescribed, treatment for TB infection is often not completed since it involves patient compliance for a prolonged course (6-9 months). Past results of school screening have varied. Mass school screening in New York, NY, showed a less than 3% positive TST result rate and was clearly not effective in finding and preventing active disease.4 However, a study5 done in Boston showed positive TST result rates of 5.1% to 8.9% in 12- to 15-year-old students. Studies6 in Australia (subjects aged 12-14 years) and Canada7 (subjects aged 3-47 years; mean, 12.6 years) reported positive TST result rates of 10% and 22.5%, respectively. In Southeast Asian adolescents (age, 16-23 years) in Los Angeles, Calif, a 55% positive TST result rate was seen.8 Although mass school screening is ineffective in detecting active TB, testing high-risk students in the school setting may be an effective way to screen these individuals. However, future cases of active TB will not be prevented unless the infected children have access to and complete a course of preventive therapy. The incidence of TB in the United States increased dramatically since the mid-1980s. In California from 1985 to 1992, there was a 30% increase in reported cases, from 3492 (13.2 cases/100000 population) to 5382 (17.2 cases/100000 population). In San Diego County, the number of reported TB cases increased from 150 (7.1 cases/100000 population) to 433 (16.5 cases/100000 population) in the same period.9 In California, the increased incidence in children has been dramatic. Between 1985 and 1992, cases in children younger than 15 years increased from 314 to 566, an increase of 80%.9 Non–US-born persons represented 70% of reported cases of TB in San Diego in 1995; Latin American and Southeast Asian immigrants comprised 60% of the total.9,10 In the United States, TB reported in non–US-born persons increased from 21.6% of total cases in 1986 to 29.6% in 1993.10 Between those born in the United States and those born outside of the United States, differences in disease rates are highest in those younger than 15 years.10 A 1990 screening project in 5 elementary schools in San Diego showed a positive TST result prevalence of 0.2% to 10.4%, with no new cases of active disease detected. Higher positive TST result rates were seen in Southeast Asian (12.2%), Latino (7.7%), and Filipino (3.2%) ethnic groups than in the white (0.7%) and African American (0.2%) populations (American Lung Association of San Diego and Imperial counties, written communication, October 30, 1990).