# Afirma Genomic Sequencing Classifier

Source: https://onco.cc/drugs/afirma/  
OnCo record `afirma` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A gene test on the needle sample from a thyroid lump that can safely call an 'uncertain' result benign and spare an operation.

## Summary

Afirma (Veracyte) was the first molecular test to change thyroid practice: the original Gene Expression Classifier (2011) and the Genomic Sequencing Classifier that replaced it in 2017 are used on Bethesda III and IV nodules, where cytology is indeterminate and 20-30% of nodules prove malignant at surgery. In the blinded multicentre validation of the GSC (JAMA Surgery 2018) sensitivity was 91% and specificity 68%, giving a negative predictive value around 96%, so about half of indeterminate nodules can be observed rather than removed. It is a laboratory-developed test covered by Medicare and most US insurers; ThyroSeq v3 is the main alternative.

## Fields

- Kind: Treatment
- Status: established
- Last checked: 2026-09-10
- Tags: test
- Brand: Afirma GSC
- Modality: RNA-sequencing rule-out classifier test (indeterminate thyroid nodules)
- Mechanism: Whole-transcriptome RNA sequencing of a fine-needle aspirate, with a machine-learned classifier trained to call cytologically indeterminate nodules benign or suspicious, plus reporting of BRAF, RET and other variants.

## Notes

- What a result means: 'benign' by Afirma carries about the same cancer risk as a benign cytology result and can be followed with ultrasound; 'suspicious' means surgery is usually advised.

## Sources

- Afirma GSC validation (JAMA Surg 2018): https://doi.org/10.1001/jamasurg.2018.1153
- Veracyte: Afirma: https://www.afirma.com

## Connected records

- cancers: [Thyroid cancer](https://onco.cc/cancers/thyroid/)
- technologies: [RNA sequencing & expression profiling](https://onco.cc/technologies/rna-seq/), [Thyroid nodule FNA, Bethesda cytology & molecular classifiers](https://onco.cc/technologies/thyroid-fna-molecular/)
- companies: [Veracyte (Decipher)](https://onco.cc/companies/veracyte/)
- terms: [Sensitivity and specificity](https://onco.cc/terms/sensitivity-specificity/)
- key papers: [Performance of a Genomic Sequencing Classifier for the Preoperative Diagnosis of Cytologically Indeterminate Thyroid Nodules](https://onco.cc/key-papers/paper-patel-jama-surg/)

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