Test Method


CPT Code

88342 x 1
88341 x 1

Stains / 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, subependymal, 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

(1) H&E slide with formalin-fixed, paraffin-embedded (FFPE) tissue, fixed with 10% NBF.
One (1) unbaked, unstained slide for H&E staining (required) and two to three (2-3) positively charged unstained slides (all cut at 4 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 & Transport

Ship specimen same day (whenever possible) with refrigerated (not frozen) cold pack

Turnaround time

1-3 days depending on level of service

Level of Service

Global (with interpretation)
Slide Only (glass slides only)
Web-Enabled (glass and digital images through eCSI portal)