Ordering Recommendation

Use to detect RET gene rearrangements in solid tumors. Does not identify the translocation partner or variant.

Mnemonic

RET_FISH

Methodology

Fluorescence in situ Hybridization (FISH)

Performed

Varies

Reported

3-7 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation
Collect

Tumor tissue.

Specimen Preparation

Formalin fix (10 percent neutral buffered formalin) and paraffin embed tumor tissue. Transport tissue block or 4 unstained, consecutively cut, 5-micron thick sections, mounted on positively charged glass slides. (Min: 2 slides) Protect paraffin block and/or slides from excessive heat.

Storage/Transport Temperature

Room temperature. Also acceptable: Refrigerated.

Unacceptable Conditions

Specimens fixed or processed in alternative fixatives (alcohol, Prefer) or heavy metal fixatives (B-4 or B-5). No tumor in tissue. Decalcified specimens.

Remarks

Include surgical pathology report with reason for referral. The laboratory will not reject specimens that arrive without a pathology report but will hold the specimen until this information is received.
If multiple specimens (blocks or slides) are sent to ARUP, they must be accompanied by one of the following: an order comment indicating that the ARUP pathologist should choose the specimen most appropriate for testing (e.g., "Choose best block"), or individual orders for each sample submitted. A Pathologist Block Selection Fee (ARUP test code 3002076) will be added to orders that utilize the first option. If multiple specimens are sent to ARUP without a request for pathologist block/slide selection or individual orders, they will be held until clarification is provided.

Stability

Ambient: Indefinitely; Refrigerated: Indefinitely; Frozen: Unacceptable

Reference Interval

By report

Interpretive Data

Refer to report. 

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Analyte Specific Reagent (ASR)

Note

Hotline History

N/A

CPT Codes

88366

Components

Component Test Code* Component Chart Name LOINC
3000685 RET FISH Reference Number
3000686 RET FISH Source
3000687 RET FISH Result
3000703 Scoring Method 81304-8
3002950 Total Cell Count 78236-7
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

RET Gene Rearrangements by FISH