Add to Favorites
Alternative Name
Glial Fibrillary Acidic Protein
Immunohistochemistry (IHC)
Test Description
Glial Fibrillary Acidic Protein (GFAP) is the major protein found in astrocytes and its expression is evidence of astroglial origin and differentiation. Gliomas are the most common cerebral neoplasm in adults and include astrocytomas, oligodendrogliomas and glioblastomas. It can also be demonstrated in ependymal cells, ependymomas, subependyomas, glioblastomas, mixed central nervous system neoplasms and gangliomas. It is detected in immature but not mature oligodendrocytes and neurons. Anti-GFAP antibodies do not cross-react with neurons, fibroblasts or muscle cells. Anti-GFAP antibodies are useful in differentiating primary gliomas from metastatic lesions in the brain and for documenting astrocytic differentiation in tumors outside the central nervous system.
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. Make sure cold pack is not in direct contact with specimen.
CPT Code(s)*
88342 x 1 or 88341 x 1
Turnaround Time
24 hours
New York Approved
Level of Service
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.