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Immunohistochemistry (IHC)
Test Description

Annexin A1 (ANXA1), a gene related to phagocytosis, is found to be one of the most highly upregulated genes in hairy cell leukemia. Annexin A1 is strongly expressed on the cell membrane of 97% of hairy cell leukemia cases. Although Annexin A1 is negative in normal B-cells or B-cell tumors other than "classic" hairy cell leukemia, it stains myeloid cells, macrophages, and subsets of benign T-cells.

Specimen Requirements
  • A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type
  • 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. Make sure cold pack is not in direct contact with specimen.

CPT Code(s)*
88342 x 1 or 88341 x 1
New York Approved
Level of Service
Stain Only
Turnaround Time

24 hours

*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.