It is important to know HOW the initial diagnosis was considered, was it just based on radiology reports? i.e., Chest X Ray
or CT scan
As the sputum c/s was negative, this excludes an active infection.
There are 2 other ways of knowing the activity of the disease:
1. The Mantoux test
- 5TU of BCG injected intradermally and response seen after 48hrs
2. The Gamma interferon
assay; if that is positive, then the chances are high and best you start the therapy.