In simple words: This code is for extra charges when a doctor removes a skin cancer using a special method called Mohs surgery.If more than 5 tissue samples need to be checked under a microscope, this code is added to the main bill.

This CPT code, 17315, represents the additional tissue block charge in Mohs micrographic surgery after the first 5 blocks have been processed.Mohs micrographic surgery is a specialized technique used to remove skin cancers, particularly those that are complex or poorly defined.The procedure involves the staged removal of tissue layers, with microscopic examination of each layer to ensure complete removal of cancerous cells.Code 17315 is reported separately, in addition to the primary Mohs surgery codes (17311-17314), for each additional tissue block beyond the initial five.The surgeon removes the tumor tissue, maps and divides it into pieces, each piece being embedded for histopathologic examination.A tissue block is defined as an individual tissue piece embedded in a mounting medium for sectioning.Routine stains (e.g., hematoxylin and eosin, toluidine blue) are included in the primary procedure codes and should not be separately billed with 17315.If non-routine stains are required, they should be reported using codes 88311-88314, with modifier 59 if needed.Repair is billed separately.

Example 1: A patient presents with a suspicious lesion on their face.Mohs surgery is performed, and 7 tissue blocks are required for complete microscopic clearance.Codes 17311-17314 (depending on the complexity of the primary procedure) and 17315 x 2 (for the two additional blocks beyond the initial five) would be reported., A patient has a large, recurrent basal cell carcinoma on their scalp.After the initial five tissue blocks, three additional blocks are needed for complete tumor removal.The appropriate primary Mohs micrographic surgery code (17311-17314) plus 17315 x 3 would be billed., A patient presents with a complex squamous cell carcinoma on their arm.During Mohs surgery, six tissue blocks are required to achieve negative margins. The surgeon bills for the primary Mohs procedure (17311-17314) and uses 17315 once to indicate the additional block.

Detailed operative report, including the number of tissue blocks processed, microscopic descriptions of each block, photographs or sketches of tissue block mapping, and pathology reports confirming negative margins.Documentation must support the medical necessity of the procedure.

** This code is only for additional blocks beyond the initial five.Each additional block requires separate reporting of code 17315.If a biopsy is performed on the same day, report a diagnostic skin biopsy code (11102, 11104, 11106) and frozen section pathology (88331) with modifier 59. Do not report codes 88302-88309 on the same specimen as part of the Mohs surgery. Do not report 88314 in conjunction with 17311-17315 for routine frozen section stain.