During the study period, 3093 eligible children were seen at the study site. No parents refused participation. Ten children were excluded because of a prior positive PPD test result. Of the 3083 who received Mantoux skin testing, 163 (5.3%) were lost to follow-up, leaving 2920 (94.7%) children. Fifty-five percent of these children were Hispanic, 44% were African American, and 50% were female. Forty-four percent of the children had no health insurance while 47% were covered by Medicaid.
The NYCDOH questionnaire identified 413 children (14%) as having at least 1 risk factor for TB. None of the children were identified as being HIV infected; hence, this item was dropped from further analysis. Of the 413 children with risk factors, 23 (5.6%) had positive skin test results, while of the 2507 children without a risk factor, 4 (0.16%) had a positive result. Children with at least 1 risk factor for TB were 35 times more likely to have a positive skin test result than those with no identifiable risk. Overall, Mantoux results were positive in 27 children (0.9%). Of the 4 children with positive skin test results not identified by the questionnaire, 3 (75%) were older than 11 years. Results of chest radiographs showed that none of the 27 children with positive skin test results had evidence of active disease.
The sensitivity, specificity, positive predictive value, negative predictive value, and OR for each screening question as well as combinations of risk factors are presented in Table 1. The full NYCDOH questionnaire had a sensitivity of 85.2%, a specificity of 86.0%, and a negative predictive value of 99.8%. Including age older than 11 years as a risk factor increased the sensitivity to 96.3% but decreased the specificity to 61.0%.