Full Press Release Details
To run the Afirma Genomic Sequencing Classifier (or GSC), Veracyte uses a dedicated FNA sample. This is because a fresh FNA sample is the proven standard for molecular testing. 1 Though some may view slide scraping as a convenient way to obtain genomic material for molecular testing, there are significant limitations to this collection methodology.
Lupo et al. Diagnostic Cytopathology 2020.
First, obtaining an adequate amount of genomic material can be a challenge. In the validation study of a molecular test touting the use of slide scraping authored by Lupo et al, 18% of samples failed to provide adequate genomic material. 2
Nikiforova et al. Cancer Cytopathology 2020.
A rate of 19% was seen in another molecular test’s validation study authored by Nikiforova et al. 3 Of greater concern, however, is the discordance of detection of molecular alterations between slide scraping and obtaining a fresh sample via FNA. In the Nikiforova publication, 17% of gene fusions and 14% of copy number alterations were missed on slide scraping relative to a matched fresh sample. 3
In fact, the discussion section of this manuscript states:
The collection of a portion of a fresh FNA sample directly into a nucleic acid preservative solution should be attempted whenever possible because this provides the highest success rate and accuracy of testing.”
Conclusion
Given these limitations, Afirma GSC is only available to order for use on a dedicated FNA pass. To learn more about implementing Afirma GSC or obtain a new test requisition form, get in touch with a Veracyte Genomic Specialist using the form below.