QuantiFERON is a blood test used to detect latent or active tuberculosis (TB) infection by measuring the immune system’s response to Mycobacterium tuberculosis antigens. It is a type of interferon-gamma release assay (IGRA) and serves as an alternative to the traditional tuberculin skin test. The QuantiFERON test requires a single blood draw and does not require a return visit for results, making it convenient for screening. It is particularly useful for individuals who have received the BCG vaccine, as it does not produce false positives related to vaccination. Results help guide further evaluation and treatment decisions.