9. Discard the challenge pack. Using the challenge pack more than once will invalidate subsequent
test results.
10. To activate the biological indicator, while wearing safety glasses,
place it in an Attest™ Biological Indicator Activator. Close and
squeeze the activator to close the 1492V 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 1492V BI:
-
in any well of a 490 or 490H Auto-reader having software
version 4.0.0 or greater and a black incubation well
configuration sticker
or
-
in an incubation well of a 490 Auto-reader having software
version less than 4.0.0 which is color-coded brown
(i.e., configured to incubate 1492V BIs) and wait for the
result. See the Auto-reader Operator's Manual for further
information related to its use.
11. Each day that a processed 1492V BI is incubated, activate
and incubate at least one non-processed 1492V BI to use as
a positive control. Follow the activation instructions provided
in Step 10 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. The positive control
BI 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.
12. Incubation and Reading:
Incubate the positive control and steam processed 1492V 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 1492V BI reading is made at:
-
24 minutes in 490 or 490H Auto-readers having software version 4.0.0 or greater
-
1 hour in 490 Auto-readers having software version less than 4.0.0.
Interpretation of Results
Fluorescent Result
The positive control (unprocessed) 1492V BI must provide a positive fluorescent result (+ on the 490 or
490H Auto-reader LCD display). Processed 1492V 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 1492V BIs, a positive (+ on the LCD display) result indicates a sterilization process failure.
A final negative (- on the LCD display) result for the processed 1492V BI after the specified incubation
time indicates an acceptable sterilization process.
Optional Visual pH Color Change Result
The 1492V BI is normally discarded after the fluorescent result has been recorded. If, however, special
studies are desired, 1492V BIs may be further incubated for a visual pH color change result. After
activation and during incubation, the white nonwoven material will absorb the bromocresol purple
indicator, the pH-sensitive indicator dye in the growth media, and appear blue. In the case of the positive
control BI a yellow color change of the growth media and/or Nonwoven Material will appear within
48 hours. Any observation of a yellow color within the vial indicates a positive result.
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