I was tested for TB because I’m on immune suppressant medication and they saw I had not been tested before I started, so they wanted it for info, I guess. I was positive, so they checked again and still positive. My chest x-ray was good, so no active TB. I found out today I have latent TB via phone call from clinical specialist nurse but she said it doesn’t matter much anyway as I’m not unwell. I’m on 25mg methotrexate once weekly for psoriatic arthritis. I left a message for my doctor but in the mean time, I googled, of course. 
not sure if methotrexate counts as being immune suppressed enough to need latent TB treatment.
Interested to hear in other people’s experiences, thanks.