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Immunohistochemistry (IHC)
Test Description
PMS2, also known as PMS1 protein homologue 2, is a DNA mismatch repair (MMR) protein. The PMS2 protein forms a heterodimer with the MLH1 protein which is then activated in the presence of ATP; this complex coordinates the binding of other proteins that repair DNA errors arising during cell preparation for cell division.
The loss of PMS2 expression in tumors can be helpful in identifying hMLH1 mutation carriers. PMS2 gene defects account for a small but significant proportion of colorectal cancers and for a substantial proportion of tumors with microsatellite instability.
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)*
88342 x 1 or 88341 x 1 (qualitative IHC) or 88360 (quantitative/semi-quantitative – manual) or 88361 x 1 (quantitative/semi-quantitative – computer assisted)
Turnaround Time
Global: 48 hours, Image Analysis (tech-only): 36 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.