Variability of the QuantiFERON®-TB gold in-tube test using automated and manual methods.

Autor: Whitworth WC; Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America., Goodwin DJ; Epidemiology Services Branch, United States Air Force School of Aerospace Medicine, Brooks City-Base, Texas, United States of America., Racster L; Epidemiology Services Branch, United States Air Force School of Aerospace Medicine, Brooks City-Base, Texas, United States of America., West KB; Department of Occupational Medicine/TB Prevention/Deployment Medicine, Wilford Hall Medical Center, Reid Clinic, Lackland Air Force Base, Texas, United States of America., Chuke SO; Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America ; Northrop Grumman Information Systems Sector, Atlanta, Georgia, United States of America., Daniels LJ; Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America ; CDC Foundation, Atlanta, Georgia, United States of America., Campbell BH; Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America ; Northrop Grumman Information Systems Sector, Atlanta, Georgia, United States of America., Bohanon J; Epidemiology Services Branch, United States Air Force School of Aerospace Medicine, Brooks City-Base, Texas, United States of America ; CDC Foundation, Atlanta, Georgia, United States of America., Jaffar AT; Epidemiology Services Branch, United States Air Force School of Aerospace Medicine, Brooks City-Base, Texas, United States of America ; CDC Foundation, Atlanta, Georgia, United States of America., Drane W; Professor Emeritus of Biostatistics, University of South Carolina, Columbia, South Carolina, United States of America., Sjoberg PA; Epidemiology Consult Services, United States Air Force School of Aerospace Medicine, Wright-Patterson Air Force Base, Dayton, Ohio, United States of America., Mazurek GH; Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2014 Jan 23; Vol. 9 (1), pp. e86721. Date of Electronic Publication: 2014 Jan 23 (Print Publication: 2014).
DOI: 10.1371/journal.pone.0086721
Abstrakt: Background: The QuantiFERON®-TB Gold In-Tube test (QFT-GIT) detects Mycobacterium tuberculosis (Mtb) infection by measuring release of interferon gamma (IFN-γ) when T-cells (in heparinized whole blood) are stimulated with specific Mtb antigens. The amount of IFN-γ is determined by enzyme-linked immunosorbent assay (ELISA). Automation of the ELISA method may reduce variability. To assess the impact of ELISA automation, we compared QFT-GIT results and variability when ELISAs were performed manually and with automation.
Methods: Blood was collected into two sets of QFT-GIT tubes and processed at the same time. For each set, IFN-γ was measured in automated and manual ELISAs. Variability in interpretations and IFN-γ measurements was assessed between automated (A1 vs. A2) and manual (M1 vs. M2) ELISAs. Variability in IFN-γ measurements was also assessed on separate groups stratified by the mean of the four ELISAs.
Results: Subjects (N = 146) had two automated and two manual ELISAs completed. Overall, interpretations were discordant for 16 (11%) subjects. Excluding one subject with indeterminate results, 7 (4.8%) subjects had discordant automated interpretations and 10 (6.9%) subjects had discordant manual interpretations (p = 0.17). Quantitative variability was not uniform; within-subject variability was greater with higher IFN-γ measurements and with manual ELISAs. For subjects with mean TB Responses ±0.25 IU/mL of the 0.35 IU/mL cutoff, the within-subject standard deviation for two manual tests was 0.27 (CI95 = 0.22-0.37) IU/mL vs. 0.09 (CI95 = 0.07-0.12) IU/mL for two automated tests.
Conclusion: QFT-GIT ELISA automation may reduce variability near the test cutoff. Methodological differences should be considered when interpreting and using IFN-γ release assays (IGRAs).
Databáze: MEDLINE
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