Test Details: Nontuberculous mycobacteria are mycobacteria other than M. tuberculosis and M. leprae. NTM mycobacteria are also referred to as atypical mycobacteria. NTM are opportunistic pathogens placing some groups at increased risk including those with underlying lung disease or depressed immune system. Symptoms can be vague such as fever, weight loss, night sweats, decreased appetite and loss of energy.