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Part # 15050091 Rev. C
Figure 26
Empty and Polyclonal Wells (Included in Raw Cluster Count)
Figure 27
Wells With Non-PF Clusters (Shown in Gray)
Quality Scoring
A quality score, or Q-score, is a prediction of the probability of an incorrect base call. A
higher Q-score implies that a base call is more reliable and more likely to be correct.
The Q-score serves as a compact way to communicate small error probabilities. Quality
scores are represented as Q(X), where X is the score. The following table shows the
relationship between the quality score and error probability.
Q-Score Q(X)
Error Probability
Q40
0.0001 (1 in 10,000)
Q30
0.001 (1 in 1,000)
Q20
0.01 (1 in 100)
Q10
0.1 (1 in 10)
NOTE
Quality scoring is based on a modified version of the Phred algorithm. For more
information, see en.wikipedia.org/wiki/Phred_quality_score.