The Importance Of Gloved Fingertip Sampling

January 18, 2022

Gloved fingertip sampling is a key test assessing the aseptic technique of compounding personnel. The gloved fingertip test assesses the amount of microbial contamination present on workers’ gloved fingers. This test is useful for reducing the risk of cross-contamination by better ensuring that personnel engaged in compounding are not inadvertently transferring material to and from their gloved hands.

In addition to being a USP <797> requirement, gloved fingertip sampling offers the following benefits:

  • Accurate assessment of personnel aseptic handling competency
  • Direct knowledge of when and with whom additional training is required
  • Risk management against cross-contamination
  • Confidence in the safety of compounded sterile preparations

Without USP <797> fingertip testing, you may be subject to risks including:

  • Non-compliance with regulatory requirements
  • Contaminated drug
  • patient safety risks

The Gloved Fingertip Sampling Process

In the gloved fingertip test, a trypticase soy agar (TSA) medium is used to detect microbes. The media is contained on a plate. The person being tested rolls his or her fingerpads and thumb onto this media without damaging the media. The process is then repeated for the other hand, normally with a separate plate.

There are several considerations to make when testing:

  • The TSA medium must include agents to neutralize disinfectants that may be present on the fingertips, as these may disinfect the media and result in a false “negative” test.
  • Annual or semi-annual testing must be administered after the testee completes a media fill test.
  • Testees must complete successful gowning evaluation fingertip sampling upon hire.
  • Current <797> requires annual retesting (for low- and medium-risk applications) or twice-yearly retesting (for high-risk applications). This will likely become semi- annual for all in the <797> proposed revision
  • Note that manufacturing facilities adhere to even more stringent testing schedules (e.g., as often as per shift). This is intended to reinforce the importance of proper aseptic technique; assure that personnel are continuing to perform at a high level; and identify any potential risk areas.

Remember that all testing media must be properly documented before, during and after testing — including manufacturer name, lot number, expiration date, operator name, sampling date and information about which hand is being tested.

After the testee completes the testing procedure, the media is then incubated between 30 and 35 degrees Celsius for 48 hours and again between 20 and 25 degrees Celsius. At this time, the CFUs will be counted. For initial gowning qualifications, any growth is reported as a failure. When performing recurring post media fill fingertip sampling, more than 3 CFUs are reported as a failure. If no growth is observed for gowning qualification or fewer than 3 CFUs are present from a post media fill fingertip sample, the test will be <1 CFU/both hands

After the return of test results, failures must be followed up upon by implementing retraining, correcting any issues and scheduling another test.

Technical Safety Services offers a wide range of microbiological environmental monitoring services — including glove fingertip sampling kits with media, plates and containers. To learn more about how we can assist with this important compliance step, contact us today.

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