Diagnostic vs. Therapeutic Excisions
By Cathie Wilde, RHIA, CCS – Director of Coding Services, Medical Record Associates, LLC

When a pathological specimen is removed during an operative procedure and is sent to the lab, is the procedure considered diagnostic and/or therapeutic? Is excisional biopsy therapeutic or diagnostic?

The most important factor in determining the procedure as diagnostic and/or therapeutic is to assess the objective of the procedure. If the primary objective of the procedure is to establish an initial diagnosis for the patient via microscopic analysis prior to starting any kind of treatment and care plan, then the procedure is likely diagnostic. Esophagogastroduodenoscopy and colonoscopy procedure with biopsies are generally easier to determine that these are diagnostic. 

However, if the patient had a polypectomy – is this diagnostic or therapeutic? If the objective is to remove the entire polyp, this would be considered therapeutic even if the polyp is sent for pathological analysis. With removal of the polyp this is definitive treatment of the lesion. 

To identify the procedure as diagnostic, ICD-10-PCS provides the qualifier “diagnostic” in the seventh character position of the code. Guideline B3.4b of the ICD-10-PCS Official Guidelines for Coding and Reporting 2018 addresses when it is appropriate to code both a diagnostic procedure and a therapeutic procedure at the same site. If an initial biopsy is followed by a more definitive procedure at the same procedure site, both the biopsy and the more definitive treatment are coded. This is often seen with “frozen sections” during the surgical procedure. A common example of this is a breast biopsy during surgery which upon frozen section analysis reveals breast cancer and results in the performance of a partial mastectomy during the same operative episode. 

One caution is diagnostic and therapeutic paracentesis discussed in Coding Clinic 3Q 2017, p. 12-13. Only the therapeutic paracentesis is coded unless there are separate diagnostic  and therapeutic procedures performed such as a diagnostic paracentesis using a different approach or of a separate site from the therapeutic paracentesis.