ROS1 gene rearrangements are reported in 1% to 2% of lung adenocarcinomas and are associated with a response to the multi-targeted tyrosine kinase inhibitor crizotinib. ROS1 rearrangement can be detected by using IHC for ROS1 protein as an alternate screening test. We recommend that any positive results be confirmed by ROS FISH studies.
ROS1
- Immunohistochemistry (IHC)
Specimen Requirements
Preferred specimen (FFPE block):
A formalin-fixed, paraffin-embedded (FFPE) tissue block is the preferred specimen type. Use 10% NBF fixative; do not use zinc or mercury fixatives.
If submitting slides (instead of a block):
Submit the following. All slides cut at 4–5 microns. Please use positively-charged slides and 10% NBF fixative.
H&E slide: One (1) unbaked, unstained slide for H&E staining (required)
Cut Slides: Two (2) positively charged unstained slides for each IHC test/antibody ordered
Specimen identification:
Block and slide identifiers should be clearly written and match exactly with the specimen ID and specimen labeling as noted on the requisition.
A formalin-fixed, paraffin-embedded (FFPE) tissue block is the preferred specimen type. Use 10% NBF fixative; do not use zinc or mercury fixatives.
If submitting slides (instead of a block):
Submit the following. All slides cut at 4–5 microns. Please use positively-charged slides and 10% NBF fixative.
H&E slide: One (1) unbaked, unstained slide for H&E staining (required)
Cut Slides: Two (2) positively charged unstained slides for each IHC test/antibody ordered
Specimen identification:
Block and slide identifiers should be clearly written and match exactly with the specimen ID and specimen labeling as noted on the requisition.
Storage and Transportation
Slides may be stored at room temperature; transport with cold pack, making sure cold pack is not in direct contact with specimen.
NYS Clients: Please provide Date and Time of Collection.
CPT Code(s)*
88342 x 1 or 88341 x 1
Turnaround time
1-2 Days
Global: 2 Days
Tech-Only (stain only): 24 Hours
Level of Service
- Global
- Tech Only
Integrations
Request electronic integrations →
New York Approved: Yes
*The CPT codes provided with our test descriptions are based on AMA guidelines and are for informational purposes only. Correct CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed.
Biomarkers
Immunohistochemistry (IHC)
| Expression | |||||
|---|---|---|---|---|---|
| ROS1 | |||||
Last Updated: March 18, 2026