Imbalance value calculation and predictions

Note: The label 3'/5' Imbalance in the Analysis Results table relays that the imbalance value is a direct ratio of the 3' and 5' reads.

A 3'/5' Imbalance value is calculated by subtracting the number of 5' reads from the number of 3' reads, and dividing the result by the sum of all EXPR_CONTROL reads:

(3' reads - 5' reads)/(sum of all EXPRE_CONTROL reads)

We find that imbalance values are a good predictor of the presence of a fusion:

In normal samples (without a fusion), imbalance values are very low (either close to zero or negative).
In samples that contain a fusion, imbalance values are higher, with gene-specific thresholds shown in the above table.

In some cases, lower imbalance values are also good predictors of the presence of fusions, as shown in the plots linked below.

Note: These guidelines apply to samples that meet the criteria described in the sections: Minimum number of reads, Sensitivity, and High 5' expression. The values in the plots below have been based on results obtained from 75 FFPE lung cancer research samples previously tested with other technologies like FISH, IHC, and RT-PCR.