Factor Xllla by IHC

Alphabetical Test listing

Factor Xllla by IHC-12376 - Technical only, 12379 - Technical & interpretation

Factor Xllla by IHC
12376 - Technical only, 12379 - Technical & interpretation
Factor 13a

All IHC stains will include a positive control tissue

  • Factor XIIIa is used to identify dermal dendrocytes as in dermatofibromas (DF)
  • This antibody is useful to distinguish DF from DFSP; DFSP shows no or very little reactivity for Factor XIIIa, but stains for CD34
  • Factor XIIIa will also stain other types of fibrohistiocytic tumors, including atypical fibroxanthoma, fibrous papules of the nose, juvenile xanthogranulomas, and malignant fibrous histiocytoma
  • Factor XIIIa staining has also been reported in atypical fibroblasts in radiation dermatitis

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


If requested, an interpretive report will be provided



  • Factor XIII is a beta globulin found in plasma, and is a thrombin-activated calcium-dependent fibrin-stabilizing factor
  • Factor XIIIa is an antibody to the A-subunit of human coagulation Factor XIII
  • The Factor XIIIa antibody does not react with Factor XIII B-subunit
  • Factor XIIIa also reacts with a population of dermal dendritic cells, and other similar connective tissue cells (it is not known whether this antibody is labeling a cross-reacting protein or actual Factor XIIIa in these cells)
  • Factor XIIIa also reacts with some macrophages (including Kupffer cells of the liver)

Staining pattern

  • Cytoplasmic


1. Abenoza P et al: CD34 and Factor XIIIa in the differential diagnosis of DF and DFSP. Am J Dermatopathol 1993, 15(5):429-434

2. Cerio R et al: Characterization of Factor XIIIa positive dermal dendritic cells in normal and inflamed skin. Br J Dermatol 1989;121;421-431

88342 - 1st stain
88341 - each additional stain