RT Journal Article
SR Electronic
T1 Screening of HIV positive TB contacts with an interferon-gamma release assay in a congregate setting in Singapore
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP p306
VO 38
IS Suppl 55
A1 Suay Hong Gan
A1 Sugunavalli Bhoopalan
A1 Kyi Win KhinMar
A1 Timorthy M. Barkham
A1 Cynthia Bin Eng Chee
A1 Yee Tang Wang
YR 2011
UL http://erj.ersjournals.com/content/38/Suppl_55/p306.abstract
AB We used the T-SPOT.TB assay in screening HIV positive contacts of infectious TB cases in the prison setting. The test is believed, on presumptive evidence, to be more sensitive than the tuberculin skin test and QuantiFERON-TB Gold In-Tube assay in detecting latent TB infection.We report the screening of 47 HIV positive contacts around 3 infectious TB cases in the prison from 2008 to 2010. Exposure of the contacts occurred during the 1-hour daily activities. Identified contacts were screened for symptoms and examined for signs of active disease. Sputum tests for AFB smears and cultures, chest xray and T-TSPOT.TB assay were done. Diagnosis of latent TB infection was based on the T-TSPOT.TB assay, after excluding active disease. Window prophylaxis was offered if the initial test was negative and stopped if the repeat T-SPOT.TB assay done after 8-10 weeks of last exposure was negative.36 (76.6%) the contacts were tested negative by the T-SPOT.TB assay. Their median CD 4 count was 343 cells/ul and 44.4% of them were on anti-retroviral therapy. 8 contacts had positive T-SPOT.TB assay result, 2 of whom had active TB (yield of 4.3%). The indeterminate rate was 2.1%. 3 contacts completed preventive treatment while 14 contacts had window prophylaxis. During the mean follow up of 19 months (median of 21.5 months, range of 10 to 25 months), one of the T-TSPOT.TB assay negative contacts, whose CD4 count was 4 cells/ul, developed active TB 11 months after completing screening.Except in cases with extremely low CD4 count, the T-SPOT.TB assay appears to have a good negative predictive value for progression to active disease in HIV positive TB contacts in Singapore.