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Blood testing is an efficient and convenient way to test for tuberculosis

Tuberculosis (TB) is one of the leading causes of infectious disease morbidity and mortality worldwide.1 Since TB spreads from person to person easily (and has similar symptoms with COVID-19), TB testing and screening is essential for public health.

Learn about the custom resources we're making available to meet your unique TB testing needs.

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IGRA vs TST: 2 types of tests used to detect TB infection

Interferon-gamma release assays (IGRAs) are highly accurate and can help reduce overall costs versus a Mantoux tuberculin skin test (TST) that requires 2 or more patient visits. TSTs have a higher rate of false positives in Bacillus Calmette-Guérin (BCG)-vaccinated individuals.

According to the CDC, TB blood tests are preferred for:

  • People who have a difficult time returning for a second appointment3
  • Patients with compromised immune systems4
  • BCG-vaccinated patients5

There are 2 TB blood tests approved by the FDA. Quest is the only lab that offers both

Quest offers both the T-SPOT®.TB and the QuantiFERON®-TB Gold Plus (QFT-Plus) blood tests—with results available from a single visit that can be reported directly to an EHR.

  • Objective results, available from a single patient visit
  • Easy specimen collection in 1 tube
  • Approved for the immunocompromised patient as well as children ages 2+
  • Up to 54-hour stability, strict ambientb
  • Option for electronic results (reported straight to EHR)
  • Exclusive to Quest

a Quest Diagnostics has validated the use of this assay under CLIA for processing specimens more than 8 hours after collection, up to 54 hours.

b Consult with your Quest Diagnostics sales representative for more details regarding stability in your area.

  • Objective results, available from a single patient visit
  • Flexible collection options: 1 tube or 4 tubes
  • Innovative CD4+ and CD8+ T-cell response delivers a more comprehensive evaluation of a patient’s immune response
  • 48-hour stability, refrigerated
  • Option for electronic results (reported straight to EHR)

The T-SPOT®.TB test is an in vitro diagnostic test for the detection of effector T cells that respond to stimulation by Mycobacterium tuberculosis antigens ESAT-6 and CFP-10 by capturing interferon gamma (IFN-γ) in the vicinity of T cells in human whole blood collected in sodium citrate or sodium or lithium heparin. It is intended for use as an aid in the diagnosis of M tuberculosis infection. The T-SPOT.TB test is an indirect test for M tuberculosis infection (including disease) and is intended for use in conjunction with risk assessment, radiography, and other medical and diagnostic evaluations.

Up-to-date relevant warnings, precautions, side effects, and contraindications can be found at:

QuantiFERON-TB Gold Plus. This test is a blood-based interferon-gamma release assay (IGRA) used as an aid in the diagnosis of Mycobacterium tuberculosis infection. It is an immune response-based, indirect test for M tuberculosis infection (including disease) and is intended for use in conjunction with risk assessment, radiography, and other medical and diagnostic evaluations. Additional testing is needed to determine if a person who has tested positive has latent tuberculosis (TB) infection or TB disease.

This in vitro diagnostic test uses a peptide cocktail simulating ESAT-6, CFP-10, and TB7.7 proteins to stimulate cells in heparinized whole blood. Detection of interferon-γ (IFN-γ) by ELISA is used to identify in vitro responses to those peptide antigens that are associated with  Mycobacterium tuberculosis infection.



  1. CDC. Tuberculosis. Published April 6, 2020. Accessed August 25, 2022.
  2. USPSTF. Final recommendation statement: latent tuberculosis infection screening. Published September 6, 2016. Accessed August 30, 2022.
  3. CDC. Testing for TB infection. Updated August 30, 2022. Accessed September 1, 2022.
  4. Komiya K, Ariga H, Nagai H, et al. Impact of peripheral lymphocyte count on the sensitivity of 2 IFN-gamma release assays, QFT-G and ELISPOT, in patients with pulmonary tuberculosis. Intern Med. 2010;49(17):1849-1855. doi:10.2169/internalmedicine.49.3659
  5. CDC. Fact sheet: tuberculin skin testing. Updated November 2, 2020.Accessed March 9, 2022.
  6. World Health Organization. Fact sheet: tuberculosis. Published October 27, 2021. Accessed November 7, 2022.