Tuberculin Reaction in Children Treated With Isoniazid

T-Cell Profiling and the Immunodiagnosis of Latent Tuberculosis Infection in Patients with Inflammatory Bowel Disease

“…Agreement between the TST and IGRA results in this series was low (k index of 0.24 and 0.25 for the 2 IGRAs), consistent with earlier studies. A second possible reason for low agreement is that the TST would be more likely to find cases of old infections 14 ; the TST is known to remain positive long after active TB has been treated, 26 whereas IGRAs may become negative in a certain number of patients after TB infection. 25 Furthermore, the fact that TST positivity generally increases with age makes it even more unlikely that BCG vaccination was a cause of false TST positives in our series.…”

Tuberculosis in childhood

“…After initial infection, most children show tuberculin reactivity in 3-6 weeks, but occasionally it can take up to 3 months after initial infection. Tuberculin reactivity usually remains positive for the lifetime of the patient, even after treatment for TB [Hsu, 1983]. The US guidelines also differ in that TST cutoffs are based on risk categorization.…”

Validity of a self-reported history of a positive tuberculin skin test

“…At the lower end, one investigation found that 7% of children with PPD reaction sizes ≥ 10 mm had reverted their PPD (to <10 mm) at 1 year. 13 Other studies have documented higher proportions of reversions, such as 25% among nursing home patients, 14 and 41% in developmentally delayed children. 15 In a prospective multicenter study of women with or atrisk for HIV infection, the proportion of HIV-seronegative and -seropositive women who reverted their PPD status was 44% and 46%, respectively.…”