ON occasions an unexpectedly high (positive) or low (negative) result may be obtained.
There are a number of reasons that False results can occur and the guide below will help identify some of the main reasons.
False Positives
- Possible Instrument calibration problem – Run Cal Check / PCD4000 calibration.
- Light Leakage- Check Instrument lid is closing and sits correctly- run test in a dark room to check if there is any improvement. Lid should be flush with top instrument casing and magnet should be puling lid shut. Check for any contamination.
- Contaminated Remove and clean swab chamber and check again.
https://help.hygiena.com/kb-doc/how-to-clean-the-instrument/
- Check chamber plug fully closed on the base of the instrument.
- Inspect the case is not damaged in any way.
- The result is accurate and the surface is contaminated. Reclean and retest.
False Negatives
If you get a negative when you are expecting a positive the light detection is not working.
There are some known procedures to address this.
- Possible Instrument calibration problem – Run Cal Check / PCD4000 calibration.
https://help.hygiena.com/kb-doc/calcheck-negative-control-failing/
- Instrument detector shutter is not operating – Run a test and listen for 2 clicks to indicate the shutter is working
- Test reagents are not working. Rub the swab bud between your fingers and then activate and read – a high result would be expected. For a more accurate test use the Hygiena positive control test. https://www.hygiena.com/positive-control-kit-food-and-beverage.html
- Quenching of the test reagents – swab the surface and then rub the swab bud between your fingers and then activate and read- or use a positive control test (see the link to the article).
- The swab is overloaded surface contaminant see article link https://help.hygiena.com/kb-doc/obtaining-low-rlu-results-when-surfaces-or-water-samples-are-visibly-contaminated/
- Tests have not been stored correctly ie not refrigerated – Use positive control test or see 3 above
- Tests have expired.
- Using competitor swabs not designed for the EnSURE Touch instrument.
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