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IMPORTANT: THIS DOCUMENT CONTAINS OUTDATED INFORMATION.
Content provided on this page contains outdated information and instruction and should not be considered current. CGS is providing this archived information for research purposes only. This archived section contains previously issued instructions that have since been updated or are no longer applicable for Medicare billing purposes.

October 12, 2015

Immunohistochemistry Services Coding and Billing Guidelines (CM00032)

Although CPT codes 88342, 88360, and 88361 and HCPCS codes G0461 and G0462 describe immunohistochemistry (IHC) test services, each service must be selected and reported based on specific clinical indications.

Effective January 1, 2014, Medicare inactivated codes 88342 and 88343 and instructed providers to use new HCPCS codes G0461 and G0462. At present G0461 and G0462 should be reported for the standard IHC stain used to detect a wide variety of proteins, antigens and other molecules in tissue samples.

Qualitative Reporting Codes 88342, 88343, G0461, G0462

The 2014 National Correct Coding Initiative (NCCN) Manual instructs pathologists to report IHC with qualitative grading such as 1+ to 4+ with codes G0461 and G0462. The G0461 pathology report must include the following elements:

  • Antibody(ies) used
  • Cellular component (nucleus, cytoplasm, cell surface) that stains
  • Results of stain: negative, 1+ to 4+, or % of tumor staining positively
  • Controls reviewed

Semi-quantitative and Quantitative Reporting Codes 88360, 88361

Codes 88360 and 88361 for morphometric analysis were originally developed for the clinically established need in breast cancer diagnosis and prognosis, which was the rationale to add the parenthetical ("eg., Her-2/neu…") to the long descriptor.

To determine if an IHC service requires the use of code 88360 or 88361, answer the following question:

Does the peer reviewed literature and national established guidelines exist and show that a semi-quantitative and quantitative determination (with numerical measurement and stain intensity determination) are needed to report the IHC result?

Pathologists derive semi-quantitative and quantitative results by counting the number of positive cells on the slide and expressing the outcome as a percent of total cells. A common method of 'scoring' IHC involves counting positive cells to a threshold number such as 3% combined with a subjective assessment of staining intensity. Based on the equipment used in the lab, only one code 88360 (manual) or 88361 (digital cellular imaging) should be selected. The 88360 or 88361 pathology report must include the following elements:

  • Antibody(ies) used
  • Numerical quantitation
  • Staining intensity

Current literature and national guidelines ONLY supports two indications for the performance of semi-quantitative and quantitative results using CPT codes 88360 and 88361:

  • Breast cancer for HER2 and hormone receptor testing (CAP/ASCO guidelines)
  • Inoperable, locally advanced, recurrent or metastatic adenocarcinoma of the stomach or esophagogastric junction for patients under consideration for trastuzumab therapy (HER2)

Note: HER2 overexpression may be performed by IHC, FISH, or other in situ hybridization method.

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