Alternative Name
BRCA1-associated protein 1
Immunohistochemistry (IHC)
Test Description

BAP1 IHC stain is a tool for detection of BAP1 mutations with subsequent inactivation. Loss of BAP1 by IHC is 100% specific for malignant mesothelioma in the context of mesothelioma vs. mesothelial hyperplasia. Loss of BAP1 may be seen in other neoplasms.

Specimen Requirements
  • A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type


  • 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)*
88342x1 or 88341x1
Turnaround Time

24 hours

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.