Design and validation of PML::RARA SHERLOCK assay for APL. (A) Illustration of PML::RARA target-specific assay design strategy with “fusion-specific” RT-RPA primers and “junction-specific” crRNA guides. (B) LOD for isoform-specific PML::RARA RNA. (C) LOD for isoform-agnostic PML::RARA RNA. (D) Heat map illustrating background-subtracted fluorescence intensity for isoform-specific and isoform-agnostic APL PML::RARA SHERLOCK using RNA extracted from patient samples. (E) Background-subtracted fluorescence from isoform-agnostic APL PML::RARA SHERLOCK performed on diagnostic PML::RARA RT-PCR–positive samples (n = 36) and control samples (n = 17). (F) Summary concordance of isoform-agnostic APL PML::RARA SHERLOCK and PML::RARA RT-PCR. RFU, relative fluorescence units.