Alternative Name
Topo I
Methodology
Immunohistochemistry (IHC)
Test Description

Topoisomerase I (TOPO1)  is essential nuclear enzyme for replication and transcription during cell reproduction and DNA repair. Upregulation of TOPO1 increases with disease stage in colorectal and pancreatic cancers.

Specimen Requirements
  • A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type

    or

  • One (1) unbaked, unstained slide for H&E staining (required) and two to three (2-3) positively charged unstained slides (all cut at 4-5 microns) for each test/antibody ordered

  • 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

Use cold pack for transport, making sure cold pack is not in direct contact with specimen.

CPT Code(s)*
88342x1 or 88341x1 qualitative; 88360x1 quantitative
Turnaround Time

Global: 48 hours, Tech-Only (stain only): 24 hours

Level of Service
Global
Stain Only

*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.