To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
To evaluate individuals at high risk for tuberculosis exposure who had a history of a positive tuberculin skin test (TST) result in order to determine the prevalence of unsuspected negative TST results. To confirm these findings with the QuantiFERON-TB test (QFT), an in vitro whole-blood assay that measures tuberculin-induced secretion of interferon-γ.
This survey was conducted from November 2001 through December 2003 at 3 sites where TST screening is regularly done. Detailed histories and reviews of medical records were performed. TSTs were placed and read by 2 experienced healthcare workers, and blood was drawn for QFT. Any subject with a negative result of an initial TST during the study (induration diameter, <10 mm) underwent a second TST and a second QFT. The TST-negative group comprised individuals for whom both TSTs had an induration diameter of <10 mm. The confirmed-negative group comprised individuals for whom both TSTs yielded no detectable induration and results of both QFTs were negative.
A total of 67 immunocompetent subjects with positive results of a previous TST were enrolled in the study. Of 56 subjects who completed the TST protocol, 25 (44.6%; 95% confidence interval [CI], 31.6%-57.6%) were TST negative (P<.001). Of 31 subjects who completed the TST protocol and the QFT protocol, 8 (25.8%; 95% CI, 10.4%-41.2%) were confirmed negative (P<.005).
A significant proportion of subjects with positive results of a previous TST were TST negative in this study, and a subset of these were confirmed negative. These individuals' TST status may have reverted or may never have been positive. It will be important in future studies to determine whether such individuals lack immunity to tuberculosis and whether they should be considered for reentry into tuberculosis screening programs.
Email your librarian or administrator to recommend adding this to your organisation's collection.