Are you choosing the right TB test for your specialty patients?
Nearly 13 million people in the US are believed to carry latent tuberculosis infection (1). Patients who are immunocompromised or who are receiving treatment for autoimmune disorders like rheumatoid arthritis face an increased risk of progression from latent TB infection to active disease (2).
The CDC now prefers TB blood tests (IGRAs), like QuantiFERON-TB Gold Plus, for the majority of the US testing population, and strongly recommends IGRAs for patients who are BCG-vaccinated or unlikely to return for a TST reading (3). Watch our on-demand webinar to learn more:
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Biologics and TB
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Disclaimer: The performance of the USA format of the QFT-Plus test has not been extensively evaluated with specimens from pregnant women or 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).
Did you know that the USPSTF now classifies latent TB screening of at-risk individuals with a Grade B recommendation – offer or provide this service? As a result, latent TB screening for at-risk adults is covered at no cost to to the patient by most private health insurance, Medicaid and Medicare (3,4).
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 (3).
• 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.
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 (4).
•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 (5)
American College of Rheumatology TB testing guidelines
In the most recent 2016 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 (6).
• 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 (7).
• 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 Society of Addiction Medicine guidelines
ASAM guidelines recommend TB testing as standard procedure for the treatment of opioid addiction (8).
• Completion of the patient’s medical history should include screening for concomitant medical conditions, including infectious diseases (hepatitis, HIV, and tuberculosis [TB]), acute trauma, and pregnancy
• Initial laboratory testing should include a complete blood count, liver function tests, and tests for hepatitis C and HIV. Testing for TB and sexually transmitted infections should also be considered
American College of Gynecology guidelines
ACOG guidelines recommend that pregnant women at high risk of TB should be tested for TB infection (9):
• High-risk groups include women who are infected with HIV, active TB contacts, and women born in countries with a high incidence of TB
1. Houben, R.M. and Dodd, P.J. (2016) The global burden of latent tuberculosis infection: a re-estimation using mathematical modelling. PLoS Med. 13, e1002152.
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. 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.
4. Bibbins-Domingo, K. (2016) Screening for Latent Tuberculosis Infection in Adults: US Preventive Services Task Force Recommendation Statement. JAMA. Sep 6, 2016.
5. 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
6. Singh, J.A. et al. (2016) 2015 American College of Rheumatology guideline for the treatment of rheumatoid arthritis. Arthritis Care Res. 68, 1–26.
7. Aberg, J.A. et al. (2014) Primary Care Guidelines for the Management of Persons Infected With HIV: 2013 Update by the HIV Medicine Association of the Infectious Diseases Society of America. Clin. Infect. Dis. 58, e1–e34.
8. 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.
9. American College of Obstetricians and Gynecologists. (2017) Frequently asked questions: pregnancy. http://www.acog.org/Patients/FAQs/Routine-Tests-During-Pregnancy
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