From the FDA Drug Label
BCG vaccination should not be administered to individuals with a positive tuberculin skin test.
A positive Tuberculin Skin Test (TST) result cannot be treated with Bacillus Calmette-Guérin (BCG) instillation, as BCG vaccination is contraindicated in individuals with a positive tuberculin skin test 1.
From the Research
Treatment of Positive Tuberculin Skin Test (TST) Result
- A positive TST result is an indication of latent tuberculosis infection (LTBI) or previous exposure to Mycobacterium tuberculosis, but it cannot be treated with Bacillus Calmette-Guérin (BCG) instillation 2, 3.
- BCG is a vaccine used to prevent tuberculosis, and its use is not recommended for treating a positive TST result 4, 5.
- The treatment for LTBI typically involves the use of antibiotics such as isoniazid, and the decision to initiate treatment is based on the results of the TST and other diagnostic tests, as well as the individual's risk factors and medical history 2, 3.
Use of BCG in Non-Muscle Invasive Bladder Cancer
- BCG instillation is used as an immunotherapy for non-muscle invasive bladder cancer, but its effectiveness and toxicity are not predicted by the TST result 4.
- The study found that the TST result did not have a value in predicting bladder cancer recurrence, progression, or cancer-specific survival, and it also did not predict therapy toxicity 4.
Diagnosis of Latent Tuberculosis Infection (LTBI)
- The TST is used to diagnose LTBI, but it can produce false-positive results in individuals who have received the BCG vaccine 2, 3, 5.
- The use of interferon-gamma release assays (IGRAs) can help to confirm the diagnosis of LTBI in individuals with a positive TST result and a history of BCG vaccination 3.
- The specificity of the TST can be improved by changing the BCG immunization schedule, as shown in a study in Japan where the vaccination schedule was changed in 2003 5.