Test Overview
Test Methodology

Fluorescence In Situ Hybridization (FISH)

Test Usage

This test detects rearrangements involving the EWSR1 gene region (22q12) via fluorescence in situ hybridization (FISH) in formalin-fixed, paraffin-embedded tissue specimens. FISH is performed using a dual color break apart probe (Abbott Molecular) to qualitatively assess for the presence of EWSR1 translocations that occur in soft tissue tumors including Ewing sarcoma/peripheral neuroectodermal tumor, desmoplastic small round cell tumor, clear cell sarcoma, angiomatoid fibrous histiocytoma, extraskeletal myxoid chondrosarcoma, and myxoid liposarcoma. Testing for EWSR1 gene rearrangement may aid in the diagnosis of these tumors.

Reference Range *

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

This test will detect rearrangements involving EWSR1, however it will not identify the translocation partner.

Test Details
Days Set Up
Monday - Thursday
Analytic Time

3 - 10 days

Soft Order Code
MiChart Code
EWSR1 (22q12) Rearrangement by FISH
  • FISH for Desmoplastic Small Round Cell Tumor (DSRCT)
  • FISH for Ewing Sarcoma
  • FISH for Clear Cell Sarcoma
  • FISH for Angiomatoid Fibrous Histiocytoma
  • FISH for Extraskeletal Myxoid Chondrosarcoma
  • FISH for Myxoid Liposarcoma
  • FISH for Peripheral Neuroectodermal Tumor
Molecular Diagnostics
Molecular Diagnostics
Specimen Requirements
Collection Instructions

A formalin-fixed, paraffin-embedded tissue block containing sufficient neoplastic cells is preferred. Unstained slides (3, 4-micron slides) with associated H&E stained slide are also acceptable. Decalcified tissue or other fixatives will be accepted and the assay attempted, however these may result in failed testing due to degraded nucleic acid. Both blocks and slides should be stored at room temperature.

Normal Volume
Formalin-fixed, paraffin-embedded tissue
Additional Information

By ordering this test the clinician acknowledges that informed consent has been obtained from the patient as required by applicable state or federal laws and the ordering clinician has authorization from the patient permitting MLabs to report the test results to the ordering clinician. Test includes pathologist interpretation of results billed as a separate additional charge. This test is not available without interpretation.

CPT Code
Fee Code
Pro Fee CPT
NY State Approved