Chapter IV. Troubleshooting the BAX® System
56
BAX® System X5 User Guide
Air Bubbles in PCR Tubes
What It Looks Like
– There appears to
be no reaction within the sample data.
Note: In many cases, samples with air
bubbles may not display indeterminate
results; however, the signal peaks are
shifted away from the expected
temperature range or appear as “weak”
results.
Cause
- Air bubbles were present in the
sample liquid before PCR tubes were
loaded into the BAX® System X5
instrument. Air bubbles commonly occur
when either air is trapped under the
tablet and is not displaced by the sample
fluid, or air is present in the pipette tip
and added to the PCR tube with the
sample liquid.
Solution
- Select OPERATION > REANALYZE WELLS and follow the
screen prompts. The associated data will display as captured.
Missing PCR Tubes
What It Looks Like
- The Raw data
appears as a jagged pattern of multiple
steps. The Processed view shows
system noise at low signal levels.
Cause
- PCR tubes were not placed in
the rack according to your rack file
layout. This happens most frequently
when you are running a partial rack of
samples and mistakenly place an entire
strip of PCR tubes in the wrong column
of the rack.
Solution
– Re-label the wells in your file according to the sample
placement in the rack and assign the appropriate target. Select
OPERATION > REANALYZE WELLS and follow the screen prompts.
The associated data will display as captured.
Non-Specific Reactions
What It Looks Like
- The Processed
data shows small peaks in the 80-95°C
range and broad peaks in the 88-95°C
range. This view may also show subtle
system noise.
Causes
– Non-specific reactions may be
caused by the following:
•
Samples were not loaded into
the BAX® System cycler
immediately after hydrating
PCR tablets.
•
After lysis, samples were not
maintained at 2-8°C before
loading into the cycler.
Solution
- Repeat the assay from last enrichment. Follow all steps of
the protocol exactly as described in this User Guide or the assay’s
package insert.
