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Frequently Asked Questions

Our test strips are composed of a white inner strip that is impregnated with bacterial endospores. These spores are specially selected strains of bacteria that are very resistant to the conditions of sterilizers. This assures that if the sterilizer is capable of neutralizing these particularly hardy bacteria they are also destroying any human pathogens that may be on your instruments. The white inner strip is covered with a white outer envelope that is impermeable to bacteria. This assures that bacteria from the environment doesn’t contaminate the test, and that no bacteria from the test strip are able to spread to your sterilizer or hands.

When we receive the test strip and completed paperwork we assign each test a bio-indicator number, and we enter the test into our computer. The strip is dropped into a broth-based culture medium, and incubated for 7 days. The tubes are read daily for bacterial growth. Media from tubes with growth are applied to a slide, gram stained, and examined microscopically. After we have identified the type of bacteria that resulted in the growth we can declare the test to be either positive or contaminated, and we notify our client accordingly. An official negative result is released after the 7 day incubation time has completed.

No. The bacteria in the test strip are non-pathogenic in people with a normal immune system. Additionally, the blue outer envelope is impermeable to bacteria when dry, so it is impossible for you to come into contact with the bacteria or for your skin bacteria to contaminate the test.

Set your sterilizer according to the directions in your sterilizer manual. The spore test strips are made to work in all sterilizers, so you should be able to follow the manufacturer’s recommended settings to effectively sterilize the test strip. You should also follow any instructions regarding preheating the machine or allowing instruments to stay in the sterilizer through the entire cool-down cycle, these steps are often important components of sterilization success.

No. The experience of the test strip should mimic that of your instruments, so that the test accurately reflects whether or not the instruments are being sterilized. Run the test strip, with instruments, at whatever settings your office routinely uses for instruments.

Yes. Sterilizers are designed to run with instruments in them, so running an empty cycle can hinder a sterilizer’s ability to hold and maintain the necessary temperature. Test strips should be run in normal sized loads on the cycle your office normally uses.

No. The CDC and public health boards around the country require that a biological monitor be used to ensure that the sterilizer is actually capable of sterilizing all bacteria. The chemical indicators (such as color change spots on the bags) offer a quick way to tell if an item has been through a sterilizer cycle, but offer no information on how long the temperature was held or if the pressure was adequate. The more sophisticated chemical indicators (class five indicators) offer more information about sterilizer conditions, but don’t show with certainty that the sterilizer is capable of destroying all organisms.

No. We run a positive control daily for each lot number here in our laboratory. Our program has determined that mailing a positive control back and forth for each test strip is unnecessary, as there are no conditions encountered in the mail that resemble the time, temperature, and pressure need to successfully sterilize our test strips. If you or any inspectors have questions regarding our positive or negative controls please call us at 800 626 4692.

Retesting of positive tests

positive biological indicator strip test signifies a possible sterilization process failure. Please see culture report to see which sterilizer had the positive test and which test date the failure occurred. The sterilizer should be retested promptly to ensure sterile instruments.

Please investigate your sterilizer to determine what conditions are causing test failure.

Testing Directions:

1. Run test strip for a complete sterilization cycle.
2. Complete Retest Submission Request form.
3. Promptly return processed test strip and completed form.

Possible reasons for test failure:

•The load was not processed (Sterilizer did not start, cycle did not run completely)
•The exposure time was not appropriate for the load configuration (sterilizer was packed too tightly or contained too many packages, wet instruments in chemical vapor sterilizer)
•The cycle or equipment failed (leaky seal, dirty sterilizer, electrical interruption)
•The test strip was contaminated after sterilization (possible only with dry heat sterilizers, enclosed culture result will indicate if test was positive or contaminated)

The CDC’s “Guidelines for Infection Control in Dental Health-Care Settings 2003” is an excellent source of information for dentists, tattoo/piercing artists, or anyone else working in a setting with exposure to blood and other body fluids. This document can be found at http://www.cdc.gov/oralhealth/guidelines.htm

Tests for multiple sterilizers may be mailed in a single envelope. Please complete a submission request form for each test and use a small piece of tape to lightly attach each test strip to its accompanying submission form. We have sent you enough envelopes to send all your test strips in a single envelope. If your office is unable to send all tests at the same time or from the same location, please call us at 800 626 4692 to request additional envelopes. If you have unused envelopes remaining at the time of your next renewal you may use them for your next shipment of supplies. Please advise us when you renew if you do not need any additional envelopes. Thank you for using the University of Iowa Sterilizer Monitoring Program.

In many states the laws pertaining to dental practice require weekly biologic monitoring (spore testing) of sterilizers, in accordance with CDC recommendations. The University of Iowa Sterilizer Monitoring Program offers both monthly and weekly testing, but compliance with state sterilizer monitoring regulations is the client’s responsibility. If you are uncertain as to the requirements in your state, please contact your state dental board to assure that you are in compliance. Thank you for using the University of Iowa Sterilizer Monitoring Program.