کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2401412 | 1102337 | 2013 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Weakly positive tests and chronologic variation of the QuantiFERON assay: A retrospective appraisal of usefulness Weakly positive tests and chronologic variation of the QuantiFERON assay: A retrospective appraisal of usefulness](/preview/png/2401412.png)
SummaryObjectivesQuantiFERON Tb Gold IT (QFT) is routinely used as diagnostic tool for detecting immune reactivity towards Mycobacterium tuberculosis. When diagnosing a latent infection weakly positive results and test reproducibility must be considered.PurposeTo judge the frequency of useful information versus confusion gained by QFT in patients with immune-mediated diseases and in pulmonary outpatients.MethodsWe retrospectively analysed 1485 QFT-tests performed on 855 patients with autoimmune diseases prior to initiating biologics and on 447 pulmonary outpatients with a suspected tuberculosis infection over a period of 16 months. In 161 cases the IGRA test was erroneously repeated. After 18 months clinical, radiographic and bacteriologic evidence for tuberculosis was collected.ResultsOf all 1485 QFT-tests 247 (=16.63%) showed a positive result, 1186 (79.87%) were negative and 52 (3.50%) turned out to be indeterminate.Using the manufacturers cut-off value for the interferon-γ response, a cohort (n = 64) of weakly positive individuals (26% of all positives) was apparent. Repeated testing within ten weeks yielded negative reactivity in 69% of these patients.Of 25 IGRA positive patients who had a repeat test after one year without tuberculosis medication, 48% showed a reversion to a negative test.The frequency of indeterminate results of the IGRA was satisfying (3.5%).ConclusionIn case of only slightly elevated immune reactivity quantitative reporting of positive QFT-test results and a repeat test strategy might be of advantage for the usefulness of the test.
Journal: Tuberculosis - Volume 93, Issue 6, November 2013, Pages 647–653