2.
Sort as needed.
3.
To compare signal across all samples on a plate, select Uniform Y Scaling.
4.
Click the View Tables button to close the thumbnail pane.
Understand Quality Values (QVs)
We recommend the following ranges for QVs (set in Preferences, see “Overview“ on
• Pure bases: Low QV < 15, Medium QV = 15 to 19, High QV = 20+ (default).
• Mixed bases: Low QV < 5, Medium QV = 5 to 10, High QV > 10 (investigate to
determine the best range for your application).
Pure bases and mixed bases have the same probability of error for the associated
basecall (10
–q/10
). Note the following:
• High-quality pure bases typically have QVs of 20 or higher.
• The distribution of quality values for mixed bases differs dramatically from that
of pure bases.
• Mixed bases have a maximum QV of 20.
• Review all mixed base calls.
QV
Pe
QV
Pe
1
79.0%
30
0.10%
5
32.0%
35
0.032%
10
10.0%
40
0.010%
15
3.2%
45
0.0032%
20
1.0%
50
0.0010%
25
0.32%
60
0.00010%
Quality value
ranges
Pure base versus
mixed base QVs
Quality values (QV)
and probability of
error (Pe)
Chapter 4
Review sequencing results
Understand Quality Values (QVs)
4
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3500/3500xL Genetic Analyzer User Guide—Data Collection Software v3.1