8. To activate the biological
indicator, place it in an Attest™
Biological Indicator Activator.
Close and squeeze the activator
to close the 1491 BI cap and
crush the media ampoule. Then
remove the BI and flick it (see
pictures at right). Visually verify
that media has flowed into the
growth chamber at the bottom of
the vial. If the media hasn’t filled
the growth chamber, hold the BI
by the cap and flick it until media
fills the growth chamber. Place
the activated 1491 BI:
− in any well of a 490 or 490H
Auto-reader having software
version 4.0.0 or greater
or
− in an incubation well of a
490 Auto-reader having
software version less than
4.0.0 which is color-coded
blue (i.e., configured to
incubate 1491 BIs)
and wait for the result. See the
Auto-reader Operator’s Manual
for further information related
to its use.
9. Each day that a processed 1491 BI is incubated, activate and incubate at least
one non-processed 1491 BI to use as a positive control. Follow the activation
instructions provided in Step 8 above. Write a “C” (for “control”) and the date
on the BI label. The positive control should be from the same lot code as the
processed biological indicator. It is a good practice to use a positive control each
day a processed 1491 BI is incubated. This helps confirm:
• correct incubation temperatures are met,
• viability of spores has not been altered due to improper storage temperature,
humidity or proximity to chemicals,
• capability of media to promote rapid growth, and
• proper functioning of the Auto-reader.
10. Incubation and Reading:
Incubate the positive control and steam processed 1491 BIs in a
490 Auto-reader or a 490H Auto-reader having software version
4.0.0 or greater.
See the Auto-reader Operator’s Manual for the proper use of this equipment.
The Auto-reader will indicate a positive result as soon as it is obtained. The final
negative 1491 BI reading is made at:
− 24 minutes in 490 or 490H Auto-readers having software version
4.0.0 or greater.
− 30 minutes in 490 Auto-readers having software version less than 4.0.0.
After the results are displayed and recorded, the 1491 BIs may be discarded.
Interpretation of Results:
Fluorescent Results
The positive control (unprocessed) 1491 BI must provide a positive fluorescent result
(+ on the 490 or 490H Auto-reader LCD Display). Processed 1491 BI results are
not valid until the positive control reads fluorescent positive. If the positive control
reads negative (- on the LCD Display), check the Auto-reader Operator’s Manual
Troubleshooting Guide. Retest the Auto-reader with a new positive control.
With processed 1491 BIs, a positive (+ on the LCD Display) result indicates a
sterilization process failure. A final negative processed 1491 BI reading (- on
the LCD Display) after the specified incubation time indicates an acceptable
sterilization process.
Act immediately on any positive BI results. Determine the cause of the positive BI
following facility policies and procedures. Always retest the sterilizer and do not use
sterilizer for processing loads until three consecutive BI results are negative.
3. To reduce the risk associated with incorrect results:
• Do not place tape or labels on 1491 BI prior to sterilization or incubation.
• Do not incubate a 1491 BI if, after processing and before BI activation, it is
observed to have a broken media ampoule. Retest the sterilizer with a new
biological indicator.
• After processing, allow BI to cool for 10 minutes before incubation.
• After BI activation, ensure media has flowed to the spore growth chamber.
Monitoring Frequency:
Follow facility Policies and Procedures which should specify a BI monitoring
frequency compliant with professional association recommended practices and/or
national guidelines and standards. As a best practice and to provide optimal patient
safety, 3M recommends that every steam sterilization load be monitored with an
appropriate BI.
Directions for Use
1. Identify the 1491 BI by writing the sterilizer, load number, and processing date
on the indicator label. Do not place another label or indicator tape on the vial
or on the cap.
2. Place the 1491 BI in a representative tray configuration as recommended by
professional association guidelines or national standards for hospital practice.
Do not place the 1491 BI in direct contact with a chemical indicator as residue
could transfer to the biological indicator and affect the result.
3. Place the representative tray in the most challenging area of the sterilizer.
This is typically on the bottom shelf, over the drain, however, the sterilizer
manufacturer should be consulted to identify the area of the chamber least
favorable to sterilization.
4. Process the load according to recommended practices.
5. After completion of the cycle, take the representative tray out of the sterilizer,
and remove the 1491 BI.
6. Allow the 1491 BI to cool for 10 minutes prior to activation.
7. Check the process indicator on the top of the cap of the 1491 BI. A color change
from pink to light brown or darker confirms that the 1491 BI has been exposed
to the steam process. This color change does not indicate that the steam
process was sufficient to achieve sterility. If the process indicator is unchanged,
check the sterilizer physical monitors.
