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Elecsys® IGRA TB
IVD
For in vitro diagnostic use.
Empowering the fight against tuberculosis (TB) with accurate, accessible, and simplified IGRA testing
Tuberculosis (TB), caused by the bacterium of the Mycobacterium tuberculosis (Mtb), remains an urgent global health challenge as the world’s leading cause of death from a single infectious agent and one of the world's top 10 leading causes of death.1
Given the substantial global burden of TB and the risk of progression from infection to disease, primary healthcare interventions aimed at preventing this progression are vital.2 TB preventive treatment (TPT) is a cornerstone of TB control strategies, offering medication to individuals at high risk of developing active TB disease.3,4 Currently, there are no direct diagnostic tests for TB infection available.5,6 Instead, two indirect methods are used to identify infected individuals: skin tests—tuberculin skin tests (TST)/tuberculosis antigen-based skin tests (TBST)—and blood-based assays, mainly interferon-gamma release assays (IGRAs). Both skin tests and IGRAs are immunological tests that rely on the principle that individuals infected with M. tuberculosis will have developed a cell-mediated immune response to the bacteria.7
The Elecsys® IGRA TB assay strengthens the fight against tuberculosis. By consolidating accurate IGRA TB testing with a broad menu of more than 130 immunoassays on Roche's industry-leading cobas® e immunochemistry platforms, we eliminate handling bottlenecks in the laboratory, expand diagnostic access, and deliver reliable results that improve patient outcomes and strengthen public health response.
The Elecsys® IGRA TB assay is an in vitro diagnostic test for the qualitative detection of the T-cell-mediated immune response to M. tuberculosis (Mtb) infection (and disease) using heparinized whole blood. It is an indirect test intended to aid in diagnosing Mtb infection in individuals at higher risk of developing TB disease. It should be used alongside risk assessments and other medical and diagnostic evaluations following applicable guidelines.8
Elecsys® IGRA TB assay concept
The testing procedure involves two distinct steps. In the first step, T cells present in the patient's whole blood sample are specifically exposed to M. tuberculosis-derived antigens in the cobas® IGRA TB tubes. If the patient has been previously infected with M. tuberculosis, reactive T cells will recognize these antigens, become activated, and subsequently release IFN-γ. In the second step, the released IFN-γ is quantified in an automated immunoassay using a plasma sample derived from the previously incubated whole blood. The level of IFN-γ serves as a functional output, and an IFN-γ reactive result indicates the presence of M. tuberculosis reactive T cells, suggesting that the patient has been infected with TB.
Step 1: In vitro stimulation phase of T cells (in whole blood sample) using M. tuberculosis-derived antigens in the cobas® IGRA tubes.
Step 2: Automated ECLIA to measure Interferon-gamma in plasma, on cobas® e 402 and cobas® e 801.
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Overview
Specifications
View full tableSpecifications
Product specification |
Value |
Systems |
cobas® e 402 / cobas® e 801 analytical modules |
Testing time |
18 minutes |
Test principle |
Double-antibody sandwich assay, quantitative |
Calibration |
2-point calibration |
Quality control (samples) |
NC tube: Negative control (IFN-γ baseline levels), PC tube: positive control (T cell fitness) |
Quality control (ECLIA IFN-γ) |
PreciControl Interferon Gamma |
Specimen types |
T cell stimulation: Human whole blood (collected in Li-Heparin tubes or cobas® IGRA TB tubes); ECLIA IFN-γ: Plasma* |
Sample volume |
T cell stimulation: 3 × 1.0 mL; ECLIA IFN-γ:18 µL |
Measuring range |
0.07-160 IU/mL |
Onboard stability |
16 weeks |
Intermediate precision in positive samples |
1.4-1.9 CV% |
Technical documents
Access important product documentation including relevant certificates and other resources.
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Clinical performance
View full tableClinical performance
Mixed risk population Individuals undergoing IGRA TB testing as part of routine care |
Low risk population Healthy individuals from low burden settings and no known risks for TB infection |
Active TB population Individuals with PCR or culture-confirmed TB disease |
|---|---|---|
Agreement to Standard of Care (SoC)† N = 1852 Positive Percent Agreement (PPA): Negative Percent Agreement (NPA): |
Diagnostic Specificity‡ N = 449 95.3% (95% Cl: 92.9 - 97.1%) |
Relative Sensitivity to QTF®-Plus N = 78 100% (95% Cl: 95.4 - 100%) |
Agreement to QTF®-Plus N = 1644 PPA: 93.6% (95% Cl: 89.1 - 96.7%) NPA: 91.6% (95% Cl: 90.0 - 92.9%) |
||
Agreement to T-SPOT.TB N = 907 PPA: 83.4% (95% Cl: 77.0 - 88.7%) NPA: 91.9% (95% Cl: 89.7 - 93.8%) |
Indeterminate, invalid, or borderline results for all the methods were excluded from the calculation.
† QTF-Plus and/or T-SPOT.TB (Revvity)
‡ Negative samples with QTF-Plus and/or T-SPOT.TB
References
1. World Health Organization. Tuberculosis [Internet; updated 2025 Nov 13; cited 2026 Jan 24]. Available from: https://www.who.int/news-room/fact-sheets/detail/tuberculosis.
2. Menzies NA, Swartwood N, Testa C, et al. Time Since Infection and Risks of Future Disease for Individuals with Mycobacterium tuberculosis Infection in the United States. Epidemiology. 2021;32(1):70-78.
3. Fair E, Hopewell PC, Pai M. International Standards for Tuberculosis Care: revisiting the cornerstones of tuberculosis care and control. Expert Rev Anti Infect Ther. 2007;5(1):61-5.
4. Harries AD, Kumar AMV, Satyanarayana S, et al. The Growing Importance of Tuberculosis Preventive Therapy and How Research and Innovation Can Enhance Its Implementation on the Ground. Trop Med Infect Dis. 2020;5(2):61.
5. World Health Organization. Global tuberculosis report 2025 [Internet; updated 2025 Nov 12; cited 2026 Jan 24]. Available from: https://www.who.int/teams/global-programme-on-tuberculosis-and-lung-health/tb-reports/global-tuberculosis-report-2025.
6. Singh S, Dey B, Sachdeva KS, et al. Challenges in tuberculosis diagnosis and management: recommendations of the expert panel. J Lab Physicians. 2015;7(1):1-3.
7. Trajman A, Steffen RE, Menzies D. Interferon-Gamma Release Assays versus Tuberculin Skin Testing for the Diagnosis of Latent Tuberculosis Infection: An Overview of the Evidence. Pulm Med. 2013:601737.
8. F. Hoffmann-La Roche Ltd. Elecsys® IGRA TB Method Sheet. (v1.0). 2026-04.
9. F. Hoffmann-La Roche Ltd. Data on file.