Related Experiment Video
Updated: Jul 14, 2026
Application of Long-term cultured Interferon-γ Enzyme-linked Immunospot Assay for Assessing Effector and Memory T Cell Responses in Cattle
Published on: July 11, 2015
Discrepancy between Mycobacterium tuberculosis-specific gamma interferon release assays using short and prolonged in
Eliane M S Leyten1, Sandra M Arend, Corine Prins
1Department of Infectious Diseases, C5P, Leiden University Medical Center, RC Leiden, The Netherlands.
Insights
The 6-day lymphocyte stimulation test (LST) showed higher sensitivity for detecting latent tuberculosis infection than shorter incubation interferon gamma release assays (IGRAs). Longer incubation periods may improve IGRA sensitivity for latent TB detection.
Area of Science:
- Immunology
- Infectious Diseases
- Diagnostic Assays
Background:
- Latent tuberculosis infection (LTBI) diagnosis relies on immune-based assays.
- Sensitivity of various interferon gamma release assays (IGRAs) for LTBI detection is not well-established.
- Comparing different IGRA formats and incubation times is crucial for accurate LTBI diagnosis.
Purpose of the Study:
- To assess the impact of different IGRA formats and incubation periods on detecting latent Mycobacterium tuberculosis infection.
- To compare the sensitivity of tuberculin skin test (TST), QuantiFERON-TB Gold in-tube (QFT-GIT), enzyme-linked immunospot assay (ELISPOT), and lymphocyte stimulation test (LST).
Main Methods:
- Compared TST results with QFT-GIT, overnight ELISPOT, and a 6-day LST using M. tuberculosis-specific peptides.
- Utilized samples from 27 TST-positive individuals, 4 cured TB patients, and 9 TST-negative controls.
- Analyzed agreement between tests using kappa statistics.
Main Results:
- The 6-day LST demonstrated significantly higher positivity rates (92%) in TST-positive individuals compared to QFT-GIT (33%) and ELISPOT (46%).
- Good agreement was found between QFT-GIT and ELISPOT (kappa=0.71), and between TST and LST (kappa=0.78).
- Poor agreement was observed between short-incubation IGRAs (QFT-GIT, ELISPOT) and TST/LST.
Conclusions:
- The 6-day LST is more sensitive for detecting past latent tuberculosis infection than shorter incubation IGRAs like QFT-GIT and overnight ELISPOT.
- Discrepancies are likely due to differences in in vitro incubation periods.
- Further research is needed to determine the risk of TB development in individuals with positive LST but negative short-incubation IGRA results before widespread use for screening.
Abstract:
The sensitivities of various gamma interferon release assays (IGRAs) for the detection of past latent Mycobacterium tuberculosis infection are not known. In this study, we aimed to assess the effects of various IGRA formats and in vitro incubation periods on test outcome. The results of the tuberculin skin test (TST) were compared with those of the QuantiFERON-TB Gold in-tube (QFT-GIT) test, an overnight enzyme-linked immunospot assay (ELISPOT), and a 6-day lymphocyte stimulation test (LST) by using the same M. tuberculosis-specific peptides and samples from 27 TST-positive persons with a history of exposure to M. tuberculosis, 4 patients cured of tuberculosis (TB), and 9 TST-negative controls. Among the TST-positive persons, the LST was more frequently positive (92%; P < 0.01) than either the QFT-GIT test (33%) or ELISPOT (46%). While good agreement was observed between the QFT-GIT test and ELISPOT (kappa = 0.71) and between TST and LST (kappa = 0.78), the agreement between TST or LST, on the one hand, and the QFT-GIT test or ELISPOT, on the other, was poor. These data indicate that the QFT-GIT test and overnight ELISPOT are less sensitive for the detection of past latent TB than the 6-day LST. The observed discrepancies between these IGRAs are most likely related to differences in incubation periods. Whether TST-positive persons with positive LST results but negative QFT-GIT and ELISPOT results are at risk for the development of TB needs to be elucidated before short-incubation IGRAs can be used for the screening of individuals for latent TB before immunosuppressive treatment.
