CD33 by IHC-12376 - Technical only, 12379 - Technical & interpretation

Test info

CD33 by IHC
12376 - Technical only, 12379 - Technical & interpretation

All IHC stains will include a positive control tissue

  • CD33 is useful in the identification of cells of myeloid and monocytic lineage, and of leukemias and myeloproliferative disorders derived from these cells, including acute myeloid leukemias, chronic myeloid leukemias, granulocytic sarcomas, myeloid dysplasia and myeloproliferative diseases
  • CD33 staining may rarely be seen in precursor B-lymphoblastic leukemias, precursor T-lymphoblastic leukemias, and rare cases of classical Hodgkins disease, Burkitt lymphoma, plasma cell neoplasms
  • Identifying CD33 expression is necessary for targeted therapy using anti-CD33 drugs (gemtuzumab ozogamicin/Mylotarg)
  • This antibody may be useful in minimally differentiated AML-M0 or AML-M5 where myeloperoxidase may be negative



Submit a formalin-fixed, paraffin-embedded tissue


Formalin-fixed, paraffin-embedded (FFPE) tissue block


FFPE tissue section mounted on a charged, unstained slide


Ambient (preferred)

  • Unlabeled/mislabeled block
  • 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



  • CD33 is a protein found in the C2 domain of human CD33, mapped to chromosome 19q13.1-3
  • This antigen may possibly have a role in cell-to-cell adhesion, and is present only on committed myeloid precursor stem cells
  • CD33 is present in cells of myelomonocytic lineages, and also stains mature macrophages; cells of erythroid and megakaryocytic lineage are negative for this protein
  • Staining has been reported in placental syncytiotrophoblasts; no other non-hematopoietic staining has been reported in other epithelial or mesenchymal tissues

Staining pattern

  • Cell surface membrane and cytoplasmic


  1. Hoyer JD et al: CD33 detection by immunohistochemistry in paraffin-embedded tissues: a new antibody shows excellent specificity and sensitivity for cells of myelomonocytic lineage.Am J Clin Pathol. 2008 Feb;129(2):316-23.
  2. Yeung J et al: Genomic aberrations and immunohistochemical markers as prognostic indicators in multiple myeloma. J Clin Pathol. 2007 Dec 21.


88342 - 1st stain
88341 - each additional stain