TB Blood Testing

POWERING AFFORDABLE CARE

with an efficient 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.

People with active TB can infect up to 15 other people through close contact over the course of a year.²

TB blood testing is an efficient, convenient way to test for tuberculosis

TB blood testing is objective, and only requires 1 blood draw which can save time and improve the patient experience and compliance by eliminating the need for a second appointment.

There are 2 types of tests for TB infection:

TB blood test

Interferon-gamma release assays (IGRAs)

vs

TB skin test

Mantoux tuberculin skin test (TST)

	Objective results
	Requires a single blood draw in 1 visit with results reported directly to an EHR system
	Highly accurate, and unaffected by the Bacillus Calmette-Guérin (BCG) vaccine

	Subjective results
	Requires 2 separate appointments and manual results
	Sensitivity of 79% and specificity of 97%,³ with specificity being as low as 59% in BCG-vaccinated patients (high false positives)

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

People who have a difficult time returning for a second appointment⁴

Patients with compromised immune systems⁵

BCG–vaccinated patients⁶

TB blood tests can reduce in-person visits by 50%

Since testing can be done in a single blood draw, TB blood tests help prevent unnecessary follow-up testing and costs associated with skin tests.

Testing for TB is critical—so are the right resources

Every organization has different testing requirements, and we’re committed to providing the resources that matter to you. Simply answer a few questions to help us ensure we send you the most helpful information.

1 visit, 1 tube TB blood testing from Quest Diagnostics

There are 2 TB blood tests approved by the FDA: the T-SPOT^®.TB test, and the QuantiFERON^®-TB Gold Plus (QFT-Plus) test. Quest is the only lab that offers both—with results available from a single visit that can be reported directly to an EHR.

T-SPOT^®.TB^a

	Easy specimen collection in 1 tube
	Approved for the immunocompromised patient as well as children ages 2+
	Low false-positive rates compared to skin tests in BCG-vaccinated individuals⁵
	Indeterminate/invalid rates <1%
	Up to 54-hour stability, strict ambient^b
	Sensitivity was 95.6% [95% CI 91.6%–98.1%] in culture confirmed populations
	Specificity was 97.1% [95% CI 94.5%–98.7%] in a US low-risk population

QuantiFERON^®-TB Gold Plus

	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
	Low false-positive rates compared to skin tests in BCG-vaccinated individuals⁵
	48-hour stability, refrigerated
	Sensitivity 94%
	Specificity 97%

^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.

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: http://www.oxfordimmunotec.com/north-america/

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.

References:

CDC. Tuberculosis. Published April 6, 2020. Accessed August 25, 2022. https://www.cdc.gov/globalhealth/newsroom/topics/tb/index.html
World Health Organization. Fact sheet: tuberculosis. Published October 27, 2021. Accessed November 7, 2022. https://www.who.int/news-room/fact-sheets/detail/tuberculosis
USPSTF. Final recommendation statement: latent tuberculosis infection screening. Published September 6, 2016. Accessed August 30, 2022. https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/latent-tuberculosis-in fection-screening
CDC. Testing for TB infection. Updated August 30,2022. Accessed September 1, 2022. https://www.cdc.gov/tb/topic/testing/tbtesttypes.htm
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
CDC. Fact sheet: tuberculin skin testing. Updated November 2, 2020. Accessed March 9, 2022. https://www.cdc.gov/tb/publications/factsheets/testing/skintesting.htm

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