Prevention

The four-tier classification system of biosafety levels (1–4) described in WHO’s Laboratory biosafety manual^² provides broad guidance on basic concepts of biosafety for the development of national and international codes of practice. The challenge for managers of TB programmes and staff at laboratories, particularly in resource-limited settings, has been to interpret the generic risk-group assignments and biosafety levels into specific precautions relevant to a country’s activities.

1. WHO handbook for guideline development. Geneva: World Health Organization, 2012.

2. Laboratory biosafety manual, 3rd edition. Geneva: World Health Organization, 2004 (WHO/CDS/CSR/LYO/2004.11). (Also available from http://www.who.int/csr/resources/publications/biosafety/en/Biosafety7.pdf.)

The laboratory manager is responsible for maintaining spill response kits. Two spill response kits should be prepared: one placed outside the containment laboratory and one placed inside the laboratory. The kits should include the items listed below.

Spill response kit:

Always use sealed centrifuge buckets, and load and unload them in a BSC. If breakage occurs during centrifuging, broken tubes must be discarded in a puncture-resistant container and disposed of immediately.

Decontaminate centrifuge buckets by soaking them in a suitable disinfectant. Do not use bleach to disinfect metal parts because it causes corrosion. Alternatively, buckets may be decontaminated by autoclaving.

When a spill of infectious material occurs within a BSC, a clean-up procedure should begin immediately, and the cabinet should continue to operate.

1. Place absorbent tissue over the spill area, and apply disinfectant solution liberally.

2. If the walls of the BSC have been splashed, clean with a layer of absorbent paper towel liberally soaked in disinfectant solution.

3. Leave affected areas covered with disinfectant for 30 minutes to 1 hour.

4. Carefully collect contaminated sharps material, and place in a puncture-resistant container for disposal.