variant allele frequency
Also written as: VAF — variant allele frequency
The percentage of sequencing reads containing a specific genetic variant at a given genomic position. Critical for determining mutation burden and tumor purity in precision oncology reports.
Full Definition
Variant allele frequency (VAF) represents the proportion of sequencing reads that contain a particular genetic variant compared to the total reads at that genomic location. In precision oncology, VAF helps clinicians assess tumor purity, clonal vs. subclonal mutations, and potential therapeutic targets. Higher VAF values typically indicate dominant clones, while lower values may suggest subclonal populations or contamination with normal tissue. VAF interpretation is essential for treatment selection and monitoring disease progression.
Usage
Usage note: Always specify the threshold used for VAF calling when editing precision oncology reports.
In Context
- "The EGFR L858R mutation showed a variant allele frequency of 45%, indicating a dominant tumor clone." — molecular pathology report
- "Low variant allele frequency values may require confirmation with orthogonal testing methods." — laboratory quality assessment