Callability Report

DRAGEN automatically generates a callability report as part of variant caller metrics when running the germline small variant caller with gVCF output mode. DRAGEN appends the percent callability for each region included in the BED file specified by the test and generates a full-callability-report in both BED and CSV formats. Callability is defined as the fraction of non-N reference positions having a PASSing genotype call. The following criteria are used to calculate callability metrics:

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Callability is calculated over the gVCF.

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Multi-allelic variants are not counted.

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Decoy contigs are ignored.

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Unplaced and unlocalized contigs are ignored.

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N positions are considered non-callable.

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For regions where no variant calling was performed, callability is 0.

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A homozygous deletion counts as a PASSing genotype call for all the reference positions spanned by the deletion.