The goal of any clean room sterile compounding microbial environmental sampling program is to determine if contamination is present at unacceptable levels and to assess if processes are followed (cleaning, hand hygiene, garbing, etc.)
Notice that we are saying that the goal is to determine if contamination is “present at unacceptable levels” and not if contamination is present PERIOD. This is important to understand since we are not working in sterile rooms but rather in ISO classified clean room. The expectation is that we WILL grow something, in particularly in the anteroom.
If you currently have a sampling plan in place and you are consistently having samples come back with zero CFU then I’d ask you to consider evaluating the LOCATIONS and the TIME of day you are testing.
This is essential to ensure the quality of our environment and the safety of our patients.
Where and Time to sample:
USP <797> states that we must sample classified areas, our hoods and classified rooms. Additionally, we must sample other areas that pose the highest risk of contamination to a CSP and that represents conditions throughout the classified area(s). It is the responsibility of each facility to locate these areas by observing workflow.
Air Sampling: USP gives more specific examples of where exactly to test air. Sampling must be done inside hoods and areas of high traffic. As mentioned, this will take observation. Most likely the highest traffic areas are from your anteroom entry, to the garbing bench, to the sink, then to the area where employees complete garbing and into the buffer room. In larger anterooms, other high traffic areas may be to and from passthroughs. Nevertheless, this takes the observation to locate these areas.
Additionally, the time at which we collect our samples play an important role of the efficacy of our environmental testing program. Sampling must occur when there are the most people present and during the busiest compounding times. Therefore, if your facility requires three people at any given time to compound, you must test with three people compounding. Doing otherwise would not meet the requirements of “representing conditions throughout the classified area”. You would not know how three people would impact you compounding area unless you sample with three people.
Surface Samples: For surfaces, USP again gives us specific areas to sample as well. These areas are inside the ISO 5 hood, equipment inside the hood, areas around the hood (i.e., carts, tables used to stage prior to introducing items inside the hood), and passthroughs. Additionally, you will want to test areas of high touch, since contamination present at these areas could spread throughout your rooms and lead to potential contamination of your final CSP.
As with air sampling, it is important to select the popper time to sample. You will want to sample surfaces after your busiest compounding session and prior to cleaning. Again, indentation of these areas takes observation. Without proper processes in place, these high touch surfaces are potential sources of contamination to your total environment through cross contamination of other areas and into your direct compounding area, increasing the risk of contaminating a CSP.
Special note for surface sampling: Remember that media used to sample surfaces must contain a neutralizing agent, such as lecithin and polysorbate 80, to neutralize cleaning product residues. This will be discussed in detail in another blog post.
Documentation of your Sampling Plan:
Once you have identified your sites for sampling (both air and surface), it is required to have a map of your IV room with the sites identified. This is so workflow and efficacy of sample choices can be evaluated. You can draw the map yourself or ask your certification company for a blank copy. You can sketch in hoods, tables, carts, shelves, etc. Then indicate the places to be sampled with a number. This number will then be used in a log that gives all the information needed to trend your future data and for inspectors evaluating your rooms.
Below is an abbreviated selection of a surface sampling log:
Note that each of the following must be present for tracking purposes.
Date: To show sampling is done on schedule (i.e., monthly) and to give a time period to investigate a failed sampling session
Time: To show that sampling is done at appropriate times (during busiest times and after compounding session, prior to cleaning)
Identifier: This will be the location identifier that can be reference to your map (i.e., number)
Person Doing the Sample: To identify the person doing the sampling so that credibility of the person can be verified if questioned
Location: This will be brief description of the area being sampled – Example, 5-foot hood, cart no. 1, shelving
Description: The exact location of your sample (ex. Hood work surface center, 2nd shelf)
ISO Classification of the sample: Since each ISO classified area has different actionable levels, it is important to identify your ISO classification of the sample
Media Lot Number: To ensure quality of your samples. If need ever arises, your lot number can be traced back to the manufactures Certificate of Analysis (which you should keep on file), showing that the media was tested to support microbial growth. (NOTE: You will also want to document the manufacture name, the type of media [TSA, MEA remembering that media with neutralizing agent is required for surface sampling], and expiration date – this can be kept on a separate log if desired).
Incubation Temperature (first): The temperature incubated on day one of the sample
CFU: The number of Colony Forming Units (CFU) recovered from the first incubation session
Incubation Temperature (second): The temperature incubated on day one of the second incubation session
CFU: The number of Colony Forming Units (CFU) recovered from the second incubation session
Comments: Area to record results (specifically identification of growth to the genius level) and any other comment you would like to record
Pass/Fail: Indicating if the sample was within range of acceptable for the ISO classification
As you see, it is extremely important to choose wisely when mapping out you microbial environmental sampling plan for both air and surfaces. Simply choosing random sites does not give a true depiction of your compounding area. Never fear growing CFU on your samples and don’t fear failing a sampling session. It is through these experiences that we come to a better understanding how our rooms work, make corrective changes to ensure the integrity of our compounding area(s) and keep patients safe.
Return soon for continuation on this topic as we further discuss documentation of your environmental sampling plan, how to evaluate your sample results, how to write an action report for a failed sampling session and what you do in between failure and resolution to ensure safe compounding.
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