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Alternative Name
Glutathione S Transferase Pi
Immunohistochemistry (IHC)
Test Description
Glutathione S Transferase Pi (GSTpi) is a cytosolic enzyme that catalyzes the conjugation of toxic compounds to glutathione for transport out of the cell. Increased expression of GSTp has been demonstrated to show increased resistance to alkylating agents, such as cyclophosphamide, ifosphamide, and melphalan. GSTp is widely distributed throughout the body and has been identified in epithelial elements of thyroid, urinary, digestive track, and hepatic bile ducts. Adenocarcinomas of the stomach, kidney, uterus and ovary, as well as squamous cell tumors of the head and neck, melanomas, and carcinoid tumors of the lung all demonstrate reactivity with this antibody.
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, 88360 x 1
Turnaround Time
Global: 48 hours, Tech-Only (stain only): 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.