If M. tuberculosis is isolated in the microbiology laboratory and there is no BSL-3 laboratory available, work may proceed if BSL-3 practices are followed in the BSL-2 laboratory -- but only if the following criteria are met. In this case, the BSL of the laboratory is also known to be considered "BSL-2 enhanced".
These criteria are stated in the Clinical and Laboratory Standards Institute (CLSI) guideline, M29-A414:
- The laboratory director, in conjunction with institutional safety personnel, has reviewed the risk and determined that "BSL-2 enhanced" practices are appropriate. If it is not determined to be appropriate, the organism must be sent to a BSL-3 reference laboratory for further work.
- Additional practices and PPE must be used. These generally include:
- Controlling access to the immediate area when work is being performed
- Ensuring personnel are offered appropriate immunizations and are involved in a medical surveillance program
- Ensuring personnel have appropriate training and demonstrate proficiency before handling increased risk agents
- Wearing solid-front or wraparound gowns, respiratory protection, eye protection, and double gloves.
- Performing all work within a certified biosafety cabinet (BSC)
- Decontaminating all materials before removing them from the BSC
- Decontaminating all waste before it leaves the facility
- Decontaminating all reusable PPE (eg, powered air-purifying respirators, eye protection)
- Avoiding the use of sharps, such as glass, whenever possible
- Decontaminating laboratory equipment and work surfaces routinely and after spills, splashes, or other potential contamination
- Ensuring that reporting and follow-up procedures are in place for emergencies and accidents
14. Clinical and Laboratory Standards Institute (CLSI). Protection of Laboratory Workers From Occupationally Acquired Infections; Approved Guideline. 4th ed. CLSI document M29-A4. CLSI. Wayne, PA: 2014.
