Beyond the swab: USP 797 sterile compounding surface sampling requirements

Other surface sampling time factors to consider

As mentioned earlier, USP <797> describes the minimum frequency and timing of surface sampling, though there are other sampling time factors to consider, including: 

• Prior to initiation of new facilities and new equipment 
• After the servicing of facilities or equipment 
• In response to identified problems (e.g., recoveries on surface sampling, may increase the frequency of sampling until no recoveries are identified) 
• In response to unstable environmental conditions (e.g., unexpected downtime of engineering controls, ensure return to state of control) 
• In response to identified trends (e.g., repeated growth on gloved fingertip testing, visible contamination of work surfaces) 
• In response to changes that could impact the state of control in the compounding area (e.g. changing cleaning agent types or frequencies) 

While not required by USP <800>, environmental wipe surface sampling for hazardous drug (HD) residue should be routinely performed to validate that HD surface contamination has been effectively removed through deactivation, decontamination, and cleaning procedures. Surface wipe sampling should include equipment used in compounding, pass-through units, staging and checking areas, storage areas, and patient administration areas.

Key USP 797 surface sampling partners

While the DP is responsible for designing the surface sampling plan, the sampling activities can be completely in-sourced, completely outsourced, or a combination of internal and external resources. Key partners include working with Quality team members and Laboratory experts to determine how the surface sampling program can be designed and managed at the organizational level. Again, these details are to be described in the organization’s SOPs.  

Surface sampling is performed using a validated device containing a general microbial growth (e.g., tryptic soy agar) supplemented with a neutralizing additive (e.g., lecithin and polysorbate 80). These chemicals neutralize the effects of residual disinfecting agents to help prevent false negatives. Flat surfaces must be sampled using validated devices (e.g., plates, paddles, or slides), while irregular and difficult-to-reach surfaces may be sampled using a sterile swab wet with sterile water or a sterile neutralizing buffer. 

If in-sourcing of the surface sampling program is conducted, the incubation times and temperatures should be considered. Ensure media devices are incubated at 30^o-35^oC for no less than 48 hours before being incubated at 20^o-25^oC at least an additional 5 days. All results must be documented, and if growth exceeds action levels defined by USP <797> (or the alert levels defined by the organization), corrective and preventive action must be taken. This is where partnering with laboratory and infection control experts is helpful; they use their expertise to identify the recovered organisms and propose sources for organism growth. 

Automated compliance solutions like Simplifi 797 aid in surface sampling task compliance from sampling to recovery to ongoing staff education as pharmacy practices continue the journey to maintain and prove a state of control in your sterile compounding areas.