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The Online TST/IGRA Interpreter
Version 3.0


The following tool estimates the risk of active tuberculosis for an individual with a tuberculin skin test reaction of ≥5mm, based on his/her clinical profile. It is intended for adults tested with standard tuberculin (5 TU PPDS, or 2 TU RT-23) and/or a commercial Interferon Gamma release assay (IGRA). For more details about the algorithm used, go to the About page. The current version of the algorithm contains modifications of the original version, which was detailed in a paper by Menzies, et al. (2008). For further information see references, or contact

Please select the best response for each field:

TST Size:

IGRA Result:


Age at immigration (if person immigrated to a low TB incidence country):

Country of birth:

BCG status:
For more info, visit: BCG World Atlas.

Recent contact with active TB:

Please select all the conditions that currently apply to the patient:
(If none of these conditions apply, please leave boxes unchecked)


Once you have completed the form, click on "Submit" and your results will show up in this space.

For inquiries, and suggestions please contact