Frequency of Leaks from Conical Centrifuge Tubes.

Introduction: Threaded conical centrifuge tubes are ubiquitous in biological laboratories and are frequently used for the storage/transport of potentially biohazardous samples. However, limited data are available on how frequently and from where these tubes leak. These data are valuable for laboratory biorisk management and to inform future studies on risks arising from the routine use of laboratory consumables. Methods: The frequency of leaks from threaded conical centrifuge tubes was tested using a Glo Germ solution as a tracer. Conical tubes (15 and 50 mL) from several brands were filled, inverted, and placed on their side on the benchtop. After 1 h, the presence or absence of leaks on the benchtop surface, tube threads, and exterior was recorded. Results: We observed that liquid leaked out of tubes that were apparently properly threaded in 2% of 15 mL tubes (confidence interval [95% CI] 1.4-2.6) and 1.4% of 50 mL tubes (95% CI 0.2-1.5). After opening, liquid was found on the threads on the outside of the tube in 20% of 15 mL tubes (95% CI 10-31) and 14% of 50 mL tubes (95% CI 1-28). We did not find sufficient evidence that differences in leak rates among brands were practically significant. Conclusions: The fact that leaks were not uncommonly observed from conical centrifuge tubes suggests that mitigations for any hazard posed by a leak should be a component of every biorisk management strategy for protocols involving the manipulation of hazardous substances in these tubes. Further research should be conducted on other activities that could cause tubes to leak (such as centrifugation or vortexing) and should be completed to understand the risks associated with this consumable. Research into the costs and benefits of mitigating the risk of leaks from conical tubes is recommended.

Rate of Splashes When Opening Microfuge Tubes with Various Methods.

Introduction: Snap-cap microcentrifuge tubes are ubiquitous in biological laboratories. However, limited data are available on how frequently splashes occur when opening them. These data would be valuable for biorisk management in the laboratory. Methods: The frequency of splashes from opening snap-cap tubes using four different methods was tested. The splash frequency for each method was measured on the benchtop surface and on the experimenter's gloves and smock, using a Glo Germ solution as a tracer. Results: Splashes occurred very frequently when opening microcentrifuge snap-cap tubes, no matter which method was used to open the tube. The highest rate of splashes on all surfaces was observed with the one-handed (OH) opening method compared with two-handed methods. Across all methods, the highest rate of splashes was observed on the opener's gloves (70-97%) compared with the benchtop (2-40%) or the body of the researcher (0-7%). Conclusions: All tube opening methods we studied frequently caused splashes, with the OH method being the most error-prone but no two-handed method being clearly superior to any other. In addition to posing an exposure risk to laboratory personnel, experimental repeatability may be affected due to loss of volume when using snap-cap tubes. The rate of splashes underscores the importance of secondary containment, personal protective equipment, and good protocols for decontamination. When working with especially hazardous materials, alternatives to snap-cap tubes (such as screw cap tubes) should be strongly considered. Future studies can examine other methods of opening snap-cap tubes to determine whether a truly safe method exists.