FISH for RET (10q11.21)

Test Mnemonic


CPT Codes

  • 88377 - QTY (1)


  • FISH for RET (Tissue)
  • FISH for RET (10q11)


  • LSI 10q11

Performing Laboratory

Cleveland Clinic Laboratories

Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
2 slidesParaffin block, formalin fixedSlidesAmbientAmbientOne formalin-fixed, paraffin embedded block containing representative tissue OR unstained 4 μm tissue sections on electrostatically charged slides containing representative tumor. Tissue must be fixed in formalin NOT B5 or PREFER fixative


Environmental Condition Description
AmbientFFPE tissue blocks and slides from FFPE specimens are stable at ambient temperatures.

Days Performed

5 days per week

Turnaround Time

5 - 7 days


Name Description
Fluorescent In-Situ Hybridization (FISH) 

Clinical Info

Interphase FISH analysis utilizing a dual color, break-apart probe for the RET gene at 10q11.21. Rearrangements involving RET may be seen in individuals with late-stage, lung adenocarcinomas that are negative for EGFR and ALK rearrangements. The translocation partner gene cannot be identified in this assay. If no cells are available for analysis, no analysis charges will be incurred.

Clinical Reference

Drilon A, Wang L, Hasanovic A, et al. Response to Cabozantinib with RET fusion-positive lung adenocarcinomas. Cancer Discov 2013;3:630–5. National Comprehensive Cancer Network (NCCN) v6.2015