Did you know that the CDC recommends testing for TB with IGRAs, like QuantiFERON-TB Gold Plus, for the majority of the U.S. testing population?

Interferon-gamma Release Assays (IGRAs) are preferred by the CDC for TB testing in most risk groups, including (1):

  • Those likely to be infected with TB
  • Anyone with low or intermediate risk of disease progression
  • Those for whom it has been decided that testing for latent TB infection is warranted

IGRAs are also strongly recommended in those who are BCG-vaccinated, or unlikely to return to have their TST read.

Watch a free webinar on US TB testing guidelines with Dr. Scott Lindquist

Watch our free on-demand webinar on TB testing guidelines from the CDC and USPSTF – and learn how these guidelines impact TB testing in a primary care setting. By implementing comprehensive, risk-based TB screening programs, primary care providers can help lead US efforts to eliminate tuberculosis.

Dr. Scott Lindquist, MD, MPH,  has focused his career on underserved populations and infectious diseases, and currently serves as the State Epidemiologist for Communicable Diseases and Deputy Health Officer for Washington State.


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US TB testing guidelines broadly recommend IGRA testing

Tuberculosis (TB) screening guidelines have been updated to include the availability of modern TB infection testing methods. IGRAs, such as QuantiFERON-TB Gold Plus, address many limitations of the century-old tuberculin skin test (TST). A range of current US TB testing guidelines are summarized below:

ATS/IDSA/CDC Clinical Practice Guidelines on the Diagnosis of TB in Adults and Children

In their jointly released 2016 guidelines, the CDC, ATS and IDSA strongly recommend IGRAs for all individuals who are BCG vaccinated or unlikely to return for a TST reading (1).

Moreover:
• IGRA testing is preferred in individuals ≥5 years of age with low to intermediate risk of progression, regardless of BCG status or likelihood of returning
• IGRA or TST can be used without preference in individuals ≥5 years of age with high risk of progression
• TST is preferred for children <5 years of age but IGRA is acceptable

CDC guidelines on the use of IGRAs in TB testing

In their 2010 guidelines on the use of IGRAs in TB testing, the CDC states that an IGRA test may be substituted for TST in all situations as an aid in the diagnosis of M. tuberculosis infection (2). Moreover:

• IGRA is preferred over TST in patients who have received the BacillusCalmette-Guérin (BCG) vaccination
• IGRA is preferred over TST in patient groups with historically low rates of returning to have TSTs read
• Two-step testing is not required for IGRAs, because IGRA testing does not boost subsequent test results

For serial and periodic screening advantages of IGRAs include the ability to get results following a single visit. Two-step testing is also not required for IGRAs, because IGRA testing does not boost subsequent test results.

U.S. Citizenship and Immigration Services guidelines

Beginning October 1, 2018, the tuberculin skin test (TST) will no longer be an approved method of TB testing for USCIS immigration exams (3). All US civil surgeons must use a TB blood test (IGRA) as the initial screening method when a test for cell-mediated immunity to TB is required (including for children under 5 years of age).

American College Health Association TB testing guidelines

2017 ACHA guidelines state that screening and targeted testing for tuberculosis (TB) is a key strategy for controlling and preventing infection on college and university campuses (4). The ACHA recommends that all incoming students should be screened for risk factors for TB through a screening questionnaire.

The following guidance on the use of IGRAs is provided:
• IGRA may be used in all circumstances in which the TST is currently used
• Two-step testing is not needed with IGRAs.
• As with TST, IGRA testing should be performed on the same day as, or four weeks after, the administration of a live virus vaccine

United States Preventative Services Task Force (USPSF) TB testing guidelines

The USPSTF refers to current CDC IGRA guidelines and in 2016 classified LTBI screening for at-risk individuals with a Grade B recommendation – offer/provide this service (5).

•At-risk includes foreign-born adults from higher prevalence countries regardless of age, duration in the U.S., or co-morbidities
•At-risk also includes individuals in congregate settings, e.g. long term care, corrections, and homeless shelters

The Grade B USPSTF recommendation ensures that LTBI screening for at-risk adults is covered by most private health insurance, Medicaid and Medicare free of charge (6)

American College of Rheumatology TB testing guidelines

In the most recent 2012 update to their guidelines, the ACR recommend 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 (7).

• IGRA is preferred over TST in the same patients listed in the 2010 CDC guidelines (see above)
• IGRA can be performed as an initial test in all such 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

Infectious Disease Society of America TB testing guidelines

IDSA guidelines released in 2013 recommend that HIV-infected patients be tested for M. tuberculosis infection (8).

• IGRA can be used upon initiation of patient care and repeated when recent TB exposure is suspected
• Annual TB test should be considered for patients who test negative but have ongoing risk for TB infection
• Repeat testing is recommended in patients whose immunocompetence may have been restored with therapy
• IGRA testing is preferred over the TST for BCG-vaccinated patients

American Academy of Family Physicians TB testing guidelines

In 2009 guidance, the AAFP acknowledges the value of IGRAs in situations where TST has limitations and states that (9):

• IGRA may be substituted for TST in all situations as an aid in the diagnosis of M. tuberculosis infection
• IGRAs avoid the subjective nature of TST and are less affected by previous BCG vaccinations
• IGRAs have favorable cost benefits in healthcare settings, correctional facilities, and homeless shelters

American Academy of Pediatrics TB testing guidelines

The 2015 edition of the Red Book® from the American Academy of Pediatrics (AAP) includes updates related to Tuberculosis screenings (10).

The following guidance on the use of IGRAs in children is provided:
• IGRAs are recommended by the CDC for all indications in which TST would be used
• IGRAs are the preferred tests for TB infection in asymptomatic children 5 years and older, who have been vaccinated with BCG or are unlikely to return for skin test reading
• Efficacy of IGRAs in children has consistently been demonstrated in children 5 years and older, and some data supports the use of IGRAs for children as young as 3 years
• Until sufficient evidence is available, the TST is preferred (although IGRA is acceptable) in children under age 5

American Society of Addiction Medicine guidelines

ASAM guidelines state that completion of a patient’s medical history should include screening for tuberculosis and other concomitant medical conditions (hepatitis, HIV, acute trauma, and pregnancy) (11). In addition to testing for hepatitis C and HIV, tuberculosis testing may also be considered.

References

1. Lewinsohn, D.M. et al. (2017) Official American Thoracic Society/Infectious Diseases Society of America/Centers for Disease Control and Prevention
Clinical Practice Guidelines: Diagnosis of Tuberculosis in Adults and Children. Clin. Infect. Dis. 64, 111-115.
2. Centers for Disease Control and Prevention. (2010) Updated guidelines for using interferon gamma release assays to detect Mycobacterium tuberculosis infection — United States. MMWR 59(RR05), 1.
3. Emily Jentes, Immigrant, Refugee, and Migrant Health Branch, US Centers for Disease Control and Prevention. "News/Update: Tuberculosis IGRA testing for US civil surgeons". 16th February, 2018.
4. American College Health Association. (2017) Tuberculosis screening and targeted testing of college and university students. May 2017. 1–9.
5. Bibbins-Domingo, K. (2016) Screening for Latent Tuberculosis Infection in Adults: US Preventive Services Task Force Recommendation Statement. JAMA. Sep 6, 2016.
6. Miller, S. (2010) Administration issues regulations on first-dollar preventive care. Society for Human Resource Management, July 15 2010. www.shrm.org/resourcesandtools/hr-topics/benefits/pages/preventivecareregs.aspx
7. Singh, J.A. et al. (2012) 2012 Update of the 2008 American College of Rheumatology recommendations for the use of disease-modifying antirheumatic drugs and biologic agents in the treatment of rheumatoid arthritis. Arthritis Care Res. 64, 625.
8. Aberg, J.A., et al. (2013) Primary care guidelines for the management of persons infected with Human Immunodeficiency Virus: 2013 update by the HIV Medicine Association of the Infectious Diseases Society of America. Clinical Infectious Diseases 58, 1–34.
9. Hauck, F. R., et al. (2009) Identification and management of latent tuberculosis infection. Am. Fam. Physician. 79, 879–886.
10. American Academy of Pediatrics. Red Book®: 2015 REPORT OF THE COMMITTEE ON INFECTIOUS DISEASES. American Academy of Pediatrics; 2015; 805-831.
11. American Society of Addiction Medicine. National Practice Guideline for the Use of Medications in the Treatment of Addiction Involving Opioid Use. June 1, 2015. 1–65.

 

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Additional resources for TB control and prevention

The CDC funds four TB Regional Training and Medical Consultation Centers (TB RTMCCs) to assist in development of TB control programs. The TB RTMCCs cover all 50 states and the U.S. territories, providing:

For more information, visit the CDC RTMCC Website.

In addition, publicly accessible TB risk assessment tools have been made available for by the State of California, which may aid in the development of regional and local TB screening programs. For more information about these tools, visit the California Department of Health TB Control Branch.


Disclaimer: The performance of the USA format of the QFT-Plus test has not been extensively evaluated with specimens from individuals who have impaired or altered immune functions, such as those who have HIV infection or AIDS, those who have transplantation managed with immunosuppressive treatment or others who receive immunosuppressive drugs (e.g., corticosteroids, methotrexate, azathioprine, cancer chemotherapy), those who have other clinical conditions, such as diabetes, silicosis, chronic renal failure, and hematological disorders (e.g., leukemia and lymphomas), or those with other specific malignancies (e.g., carcinoma of the head or neck and lung), or individuals younger than age 17 years.

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