Annexin A1 by IHC-12376 - Technical only, 12379 - Technical & interpretation

Test info

Annexin A1 by IHC
12376 - Technical only, 12379 - Technical & interpretation
  • All IHC stains will include a positive control tissue
  • Annexin A1 is used to differentiate hairy cell leukemia from other B-cell lymphomas including hairy cell leukemia variant. In the differential diagnosis of hairy cell leukemia and other B-cell neoplasms, Annexin A1 has a sensitivity of 96% and specificity of 100%. Consider using Annexin A1 as part of a panel of testing (BRAF, TRAP).
  • Annexin A1 is positive in normal T-cells and myeloid cells. Positivity has also been reported in T-cell leukemias/lymphomas, AML, CMML, CML, P. vera, ET, primary myelofibrosis, mast cell disease, carcinomas, and some sarcomas.



Submit a formalin-fixed, paraffin embedded tissue block


Formalin-fixed, paraffin embedded (FFPE) tissue block


Tissue section mounted on a charged, unstained slide


Ambient (preferred)

  • Unlabeled/mislabeled
  • Insufficient tissue
  • Slides broken beyond repair


AHL - Immunohistochemistry
Mo - Fr
1 - 2 days

Immunohistochemical staining and microscopic examination

Clinical and Interpretive info


If requested, an interpretive report will be provided



Annexin A1 is a protein encoded by the ANXA1 gene. The protein has multiple functions and is upregulated in hairy cell leukemia.
Staining pattern

Membranous and cytoplasmic


  1. Sherman MJ, Hanson CA, Hoyer JD. An Assessment of the usefulness of immunohistochemical stains in the diagnosis of hairy cell leukemia. Hematopathology 2011;136:390-399.
  2. Wang HY, Zu Y. Diagnostic algorithm of common mature B-cell lymphomas by immunohistochemistry Arch Pathol Lab Med 2017;14:1236-1246.


88342 - 1st stain
88341 - each additional stain