Can someone get a tuberculosis (TB) titer, also known as an Interferon-Gamma Release Assay (IGRA) or Tuberculin Skin Test (TST), checked after receiving the Covid-19 vaccine?

Tuberculosis Testing After COVID-19 Vaccination

Yes, tuberculosis (TB) testing, including Interferon-Gamma Release Assays (IGRAs) or Tuberculin Skin Tests (TSTs), can be performed after receiving the COVID-19 vaccine without concerns about interference with test results. 1

TB Testing Methods and COVID-19 Vaccination

Interferon-Gamma Release Assays (IGRAs)

• IGRAs such as QuantiFERON-TB Gold and T-SPOT.TB are blood tests that measure the immune response to TB proteins 2
• Recent research confirms that SARS-CoV-2 vaccination does not affect IGRA interpretation or reliability 1
• IGRAs have the advantage of requiring only a single visit for blood collection, with no need to return for result reading 2
• IGRAs are not affected by prior BCG vaccination, making them preferred for individuals who have received the BCG vaccine 2

Tuberculin Skin Test (TST)

• TST requires the patient to return 48-72 hours after administration for reading of results 2
• TST specificity may be reduced in individuals who received BCG vaccination, particularly if vaccinated after infancy 3
• False-positive TST results due to BCG are minimal if vaccination was received in infancy and testing occurs ≥10 years after vaccination 3

Recommendations for TB Testing

When to Use IGRAs vs. TST

• IGRAs are preferred for:

  • Individuals who have received BCG vaccination 2
  • Persons who may have difficulty returning for TST reading (e.g., homeless persons) 2
  • Those needing more specific results due to concerns about false positives 4

• TST is preferred for:

  • Children under 5 years of age 2

• Either test may be used without preference for:

  • Recent contacts of persons with active TB (with follow-up testing 8-10 weeks after exposure if initial test is negative) 2
  • Periodic screening of healthcare workers or others with occupational exposure 2

Special Considerations

• For individuals at high risk for TB infection or progression to active disease, using both TST and IGRA may be considered to increase diagnostic sensitivity 2
• For immunocompromised patients, IGRAs may be more sensitive than TST 5
• Prior to implementing IGRA testing, arrangements should be made to ensure proper blood collection and timely testing 2

COVID-19 Vaccination and TB Testing

• Recent studies show that COVID-19 vaccination does not significantly affect the reliability of IGRAs 1
• The indeterminate rate of IGRAs is not increased by COVID-19 vaccination 1
• There is no need to delay TB testing after receiving COVID-19 vaccination 1

Practical Implementation

• When ordering an IGRA, ensure that blood is collected in the proper tubes and testing is performed within the required timeframe 2
• For serial testing (such as for healthcare workers), using the same test format for repeat testing will minimize conversions that occur due to test differences 2
• For individuals with recent TB exposure, negative results obtained prior to 8 weeks after exposure should be confirmed by repeat testing 8-10 weeks after the end of exposure 2

In conclusion, TB testing can be safely and effectively performed after COVID-19 vaccination without concerns about interference with test results. The choice between IGRA and TST should be based on individual factors such as BCG vaccination status, age, and likelihood of returning for test reading.