The CDC and other medical organizations prefer interferon-gamma release assays (IGRAs) for certain patient populations—here’s why you should, too

IGRAs offer many advantages over the tuberculin skin test

With a single visit and a highly accurate, objective result unaffected by the BCG* vaccine, IGRAs are the preferred method for many patient types compared to the century-old Mantoux tuberculin skin test (TST). When you’re ready to make the switch, only Quest Diagnostics offers a choice of tuberculosis (TB) blood tests: T-SPOT®.TB and QuantiFERON®- TB Gold Plus (QFT-Plus), both of which have a single-tube collection option.

*Bacille Calmette-Guérin

TST: subjective reading/interpretation Mantoux tuberculin skin test
  • Two patient visits required1
  • Manual results entry
  • Sensitivity 95%–98% in patients with proven active tuberculosis,2 specificity as low as 59% in BCG-vaccinated patients (high false positives)3

*The photograph was originally published in the Valley Echo and has been reproduced with the permission of the Lung Association of Saskatchewan.

TB blood tests: objective resulting T-SPOT®.TB and QFT-Plus

The new: TB blood tests
T-SPOT®.TB and QuantiFERON®-TB Gold Plus

  • Results available from a single patient visit1
  • Option for electronic results (reported straight to EMR)
  • T-SPOT.TB – estimated sensitivity: 95.6%†,4; estimated specificity: 97.1%††4
  • QFT-Plus  – estimated sensitivity: 94.09%†††,5; estimated specificity: 97.27%††††5
  • Flexible collection options: 1-tube or 4-tube
Groups with poor rates of return for TST reading1
Individuals who have received BCG vaccination1 
USCIS immigration exams6
Quest Diagnostics is committed to providing the most advanced TB screening available, in accordance with clinical guidelines.

Tuberculosis screening guidelines have been updated to include modern TB infection testing methods, including interferon-gamma release assays or TB blood tests, to address the limitations of the tuberculin skin tests.

The United States Preventive Services Task Force7

Grade B recommendation:

  • Screening for latent TB infection in populations atincreased risk
    • Foreign-born adults from higher prevalence countries, regardless of age, duration in the US, or co-morbidities
    • Individuals in congregate settings
  • Ensures LTBI screening for at-risk adults is covered by most private health plans, Medicaid, and Medicare
American Thoracic Society, Infectious Diseases Society of America, and CDC2
  • IGRAs are preferred for patients > 5 years of age with low to intermediate risk of progression, regardless of BCG status or likelihood of returning2
  • IGRA or TST can be used without preference in individuals > 5 years of age with high risk of progression2
  • TST is preferred for children < 5 years of age, but IGRA is acceptable2
  • American Academy of Family Physicians (AAFP) endorses these guidelines8
American Academy of Pediatrics9
  • Interferon-gamma release assays or tuberculin skin test can be used to detect TB infection among at-risk children > 2 years of age
  • IGRAs are preferred for children who are BCG-vaccinated or unlikely to return
  • Children with HIV infection should receive annual IGRA testing or TST
  • Risk assessment for TB should be performed at the first encounter and then annually
American College of Rheumatology10
  • TB screening in all rheumatoid arthritis (RA) patients being considered for therapy with biological agents, regardless of the presence of risk factors for TB infection
  • IGRA is preferred if patient has a history of BCG-vaccination
  • IGRA can be performed as an initial test in all RA patients, in annual testing, and where TB exposure is likely
  • In immunosuppressed RA patients with risk of TB exposure, a repeat test can be considered 1–3 weeks after initial negative result
  • Annual TB screening in RA patients who live, travel, or work in environments where TB exposure is likely while continuing treatment with biologics

Your Quest representative can help you decide which TB blood test may best serve your practice. Either option includes additional advantages from Quest, including broad health plan coverage, access to a single-tube draw option, and easy test ordering and tracking through our Quanum™ Lab Services Manager.

Test name Test code CPT codea
T-SPOT®.TB Coming soonb 86481
QuantiFERON®-TB Gold Plus, 1 Tube 36970(X) 86480
QuantiFERON®-TB Gold Plus, 4 Tubes, Draw Site Incubated 36971(X) 86480

a The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

b T-SPOT®.TB is available through Oxford Immunotec until the Quest Diagnostics national test code is available.

Questions? Call 1.866.MYQUEST (1.866.697.8378)