All specimens suspected of containing M. tuberculosis (including specimens processed for other microorganisms) should be handled in a Class I or II biological safety cabinet (BSC). Appropriate personal protective equipment (PPE) must be used. At a minimum, this includes gloves and fluid-resistant laboratory coat or gown.
Non-aerosol-producing manipulations (eg, preparing direct smears for acid-fast staining when done in conjunction with training and periodic checking of competency) can be performed using biosafety level-2 (BSL-2) practices and procedures, containment equipment, and facilities.
BSL-3 practices, safety equipment, and facility design and construction are applicable to microbiology laboratories that work with indigenous or exotic agents with a potential for respiratory transmission, and which may cause serious and potentially lethal infection. If the laboratory is propagating and manipulating cultures for M. tuberculosis, BSL-3 practices, containment equipment, and facilities are required. Barriers include controlled access to the laboratory and ventilation requirements that minimize the release of infectious aerosols from the laboratory. Secondary barriers should include self-closing double-door access and negative airflow into the laboratory. Exhausted air must not be recirculated.
Work surfaces must be decontaminated, using the laboratory-approved disinfectant, upon completion of procedures, immediately following a spill, and at the end of the work shift, if the surface was recontaminated since the last cleaning. Laboratory equipment should be routinely decontaminated.
Hands must be washed upon completion of work with potentially infectious materials and before leaving the laboratory.