How does the diagnosis of NTM infection be made?

I just read more about Nontuberculosis Mycobacterium (NTM). I read that NTM it's like the cousin of TB.. 

I wonder how the doctor diagnose a patient with NTM. Is it same like diagnosing a TB? Like checking the sputum (+culture). I don't know whether NTM was also assessed in sputum assessment..

I did some sputum check many times, but only for checking the TB. All of the result was negative (no TB bacteria was found). However I did start a TB treatment, my doctor gave this treatment.. I drink regularly and already stop.

Infection is quite hard to deal with, if the management is not right. Well I hope in my place (Indonesia) many doctors will aware of this. Cheers.