Frequently Asked Questions
How often should biological monitoring (spore testing) be performed in a dental practice?
In the United States, biological monitoring should be performed at least weekly, as recommended by the CDC and most state dental boards.
In addition to routine testing, when should a spore test be performed?
Spore tests should also be conducted at the following instances, and as recommended by local infection control guidelines:
• After installing or relocating a sterilizer
• Following sterilizer malfunctions or major repairs (e.g., chamber door, vacuum pump, plumbing, or control system rebuilds)
• After a failed sterilization cycle
• With every load that includes implantable devices
• When changing packaging materials (i.e., pouches, wrap or tape), cassettes or trays
• After training new staff in instrument reprocessing
• Following changes to sterilization procedures or load configuration
Should a BI be run on a full or empty sterilizer chamber?
For accurate results with tabletop units (commonly used in dental practices), BIs should be placed in a standard load to simulate real-use conditions.
What is the proper location for placing a BI in the sterilizer?
The BI should be placed in the most challenging area of the sterilizer chamber—typically on the bottom tray over the drain or near the door, where air pockets are most likely to occur —always following the manufacturer’s instructions for use (IFUs). To ensure thorough monitoring, alternate the placement location weekly.
If placing the BI horizontally, position it directly on the tray beneath the instrument packages (not on top of them), ensuring it sits on the bottom tray and underneath the load.
Can a BI be placed in a sterilization pouch?
In the United States, the BI may be placed directly on the tray or inside a sterilization pouch. Using a pouch helps simulate real-use conditions and encourages proper horizontal placement. It also makes the vial easier to locate after the cycle, reducing the risk of it being lost or mishandled.
How should test and control vials be labeled?
All vials should be labeled with the date, sterilizer number or identifier, and load or cycle number.
When testing multiple sterilizers, the control vial may be labeled simply with “CONTROL” and the date. If more than one control is used in a day (e.g., for separate test batches), number them clearly (e.g., “Control #1,” “Control #2”) to match their corresponding test vials.
What is the function of a control vial?
The control vial confirms that the spores in the biological indicator are viable. It remains unprocessed and is incubated alongside the test vial. A valid control should show microbial growth (e.g., yellow color change) after incubation.
When is a control vial required?
A control vial must be used with every BI test. It must come from the same lot as the test vial and be incubated at the same time and under the same conditions. A BI test without a control is considered invalid.
Can one control vial be used for multiple sterilizers or test vials?
Yes—but only if all test vials are processed around the same time and will be incubated together. A single control vial can be used for that batch. If a BI test is run later in the day and will be incubated separately, a new control vial is required, even if the sterilizer or BI lot is the same.
Example: If a BI test is performed at 9:00 AM and another at 2:00 PM, each requires its own control vial, incubated with the corresponding test vial.
What types of sterilizers are compatible with the Medicom AssureCheck™ 10H BI?
The AssureCheck™ 10H BI is compatible with steam sterilizers, including gravity displacement, pre-vacuum (dynamic air removal), and SFPP (steam-flush pressure-pulse) sterilizers.
When should BI vials be crushed and incubated?
BI vials should ideally be crushed and incubated within 2 hours of the sterilization cycle ending. Wait to crush and incubate until all test vials from the same batch have completed processing so they can be incubated together with the control vial.
How long should a BI vial cool before crushing?
Allow the test vial to cool for at least 10 minutes after processing. This helps reduce internal pressure and prevents breakage during crushing.
Should test and control vials be incubated together?
Yes. To ensure valid results, the control vial must be incubated at the same time as all test vials from the same batch. Wait until all test vials are ready, then crush and incubate all vials together.
What is the correct incubation temperature for the Medicom AssureCheck™ 10HR BI?
The AssureCheck™ 10HR BI must be incubated at 60°±2°C. This temperature range is critical for accurate test performance.
For best results, use the AssureCheck™ Dry Block Incubator. If using another incubator, it must reliably maintain the required temperature.
What is the required incubation time to ensure valid results?
Incubate all BI vials for the full 10-hour cycle. Shortening the incubation time may result in missed or inaccurate results.
If the BI changes color after a few hours, is full incubation still required?
Yes. Even if a BI shows early color change, it must be incubated for the full 10 hours to confirm the result.
How long should the incubator be plugged in before use? Why does the LED flash?
The incubator should be plugged in and allowed to warm up for at least 20 minutes, or as specified in the IFUs. This ensures it reaches the correct operating temperature. Flashing LEDs typically indicate that the unit is in its normal pre-heating phase. If an error code appears (e.g., E#), refer to the IFUs for specific troubleshooting instructions.
What color change occurs in the BI when sterilization fails?
If sterilization fails, the BI’s growth media will change from purple to yellow after incubation, indicating the presence of viable spores.
What if the control vial remains purple after incubation?
If the control vial remains purple, it is an indication that the spores were not viable, or incubation conditions were incorrect. The test is therefore invalid.
Why does the control vial appear brownish rather than yellow following incubation?
A brownish or bourbon color may indicate partial growth or incubation issues. In contrast, a bright yellow (or amber) indicates a definitive failure.
Why does the vial liquid appear cloudy after incubation?
Cloudiness may result from spore germination or contamination, but it does not confirm a failed result on its own. Evaluate it alongside color change and control results to determine test validity.
How can the test and control BI vials be differentiated after incubation?
Label each vial clearly before incubation and place them in separate slots. After incubation, the control vial should appear yellow, confirming spore viability. The test vial will remain purple (pass) or turn yellow (fail). The test vial can also be identified by its chemical indicator (CI) stripe, which should have changed color following sterilization processing.
What should be done after an initial BI test failure?
If a BI test indicates a possible sterilization failure:
• Stop using the sterilizer immediately.
• Notify your Infection Control Lead or designated personnel.
• Quarantine all instruments from the failed load—and any items processed since the last passed BI test result.
• Review equipment and processing procedures to identify potential errors.
• Once the issue has been identified and corrected, repackage and reprocess the instruments in the same sterilizer using the same cycle parameters. Include new physical, chemical, and biological indicators.
• If the repeat BI test passes, return the sterilizer to service. If the repeat test fails, follow the steps outlined for a consecutive failure.
What should be done after a consecutive BI test failure?
If a second BI test fails after retesting:
• Remove the sterilizer from service until the issue has been fully identified and corrected.
• Recall all instruments processed in that sterilizer since the last confirmed negative BI test. Repackage and reprocess them in a validated, fully functioning alternate sterilizer.
• Contact a qualified technician to inspect, diagnose, and repair the unit.
• After service, perform three consecutive standard-load cycles using the same cycle parameters and representative instruments.
• Include a new BI vial and chemical indicators in each cycle. Cycles must be run separately (not simultaneously).
• The sterilizer can only be returned to service if all three BIs pass. If any of the three tests fail, the sterilizer should be evaluated and repaired if necessary.
Does a passing BI result guarantee that all instruments are sterile?
A passing BI indicates effective sterilization conditions were met at the time and location of the BI placement. However, it does not prove that every item in the load is sterile. Proper instrument cleaning, packaging, loading, and cycle selection must also be followed to ensure full sterilization.
What should be done if the chemical indicator on the BI did not change color?
If the CI stripe on the BI fails to change color after processing, this may signal a processing error, equipment malfunction or a possible issue with the BI itself. In this case, the BI test is considered invalid and must be repeated. If the issue appears related to the BI vial, contact the manufacturer for support or replacement.
What sterilization options can be used after a failed BI test?
If sterilization is required while the primary sterilizer is out of service:
• Use a backup sterilizer that has a recent passing BI result,
• Request a loaner sterilizer from the distributor, or
• Send instruments to a licensed off-site sterilization service.
Do not use the sterilizer that failed until it has been inspected, corrected, and successfully rechallenged as required, with passing BI results.
What documentation is required for biological monitoring?
Keep records of each BI test and control results, including:
• Date and time
• Sterilizer ID
• BI lot number (Canada only)
• Test and control results
• Person responsible
These records should be kept for at least 3 years or as required by your local regulatory body.
How should used/yellow vials be disposed of?
After incubation, vials with purple media (no spore growth) can be disposed of in the regular trash.
Vials showing spore growth (yellow) should be packaged in a sterilization pouch and reprocessed in the sterilizer as per manufacturer's instructions. This helps ensure that viable microorganisms are not introduced into the waste stream, supporting safe and environmentally responsible disposal.
Are the contents of the BI vials hazardous?
No. The spores used in BIs are non-pathogenic and classified as biosafety level 1. They are not disease-causing and are safe to handle using standard precautions.
How should the box of BIs be stored?
Store biological indicators in a cool, dry place, away from direct sunlight, heat and chemicals. Always follow the storage guidelines on the packaging to maintain product integrity and shelf life.
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