The TB1-NIL biomarker is integral to the QuantiFERON-TB Gold Plus (QFT-Plus) assay, a diagnostic tool used to detect Mycobacterium tuberculosis infection. In this context, 'NIL' refers to the baseline interferon-gamma (IFN-γ) level measured without antigen stimulation, serving as a negative control to account for non-specific background activity. The TB1 tube contains antigens that primarily stimulate CD4+ T-cell responses. By subtracting the NIL value from the TB1-stimulated IFN-γ level (TB1-NIL), clinicians can assess the specific immune response to TB antigens. A TB1-NIL value of 0.35 IU/mL or higher typically indicates a positive result, suggesting a TB infection. This method enhances the accuracy of TB diagnosis by distinguishing specific immune responses from background noise.
TB1-NIL
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