Immunohistochemistry Stain Form Recommended (ARUP form #32978)

Ordering Recommendation

Determine eligibility for tyrosine kinase inhibitor (TKI) (eg, crizotinib) therapy, primarily in individuals with pulmonary adenocarcinomas. Detects ROS1 fusion proteins (IHC) and ROS1 gene rearrangements (FISH).

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Tumor tissue

Specimen Preparation

Formalin fix (10 percent neutral buffered formalin) and paraffin embed tissue. Transport tissue block or 6 unstained (3- to 5-micron thick sections), positively charged slides in a tissue transport kit (ARUP supply #47808) available online through eSupply using ARUP Connect or contact ARUP Client Services at (800)522-2787. (Min: 6 slides) If sending precut slides, do not oven bake.

Storage/Transport Temperature

Room temperature or refrigerated. Ship in cooled container during summer months.

Unacceptable Conditions

Paraffin block with no tumor tissue remaining. Specimens fixed in any fixative other than 10 percent neutral buffered formalin. Decalcified specimens.


Include pathology report. IMMUNOHISTOCHEMISTRY ORDERING AND SUBMISSION DETAILS: Submit electronic request. If you do not have electronic ordering capability, use an ARUP Immunohistochemistry form (#32978) with an ARUP client number. For additional technical details, please contact ARUP Client Services at (800) 522-2787.
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.


Ambient: Indefinitely; Refrigerated: Indefinitely; Frozen: Unacceptable


Semi-Quantitative Immunohistochemistry (IHC)




1-5 days
If reflexed, add 3-5 days.

Reference Interval

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

Laboratory Developed Test (LDT)


If ROS1by Immunohistochemistry result is equivocal or positive, then ROS1 by FISH will be added. Additional charges apply.

Hotline History


CPT Codes

88342; if reflexed, add 88366


Component Test Code* Component Chart Name LOINC
2008415 ROS1 by IHC Result 55229-9
2008417 ROS1 Client Block ID 94736-6
3003121 ROS1 Tissue Source 31208-2
* 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.


  • ROS1 IHC
  • ROS1 IHC with Interpretation
  • ROS1 immunostaining
ROS1 with Interpretation by Immunohistochemistry with Reflex to FISH if Equivocal or Positive