Gastroenterology Coding Alert

Question: When a patient comes in for a surveillance colonoscopy with an initial diagnosis of Z09 and Z86.0100 and the provider finds additional polyps during the colonoscopy, do we code as: Z09, Z86.0100, and K63.5; or K63.5 only? For anesthesia coding, how may this affect the modifier used? Please advise.

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Answer: Generally, code Z09 (Encounter for follow-up examination after completed treatment for conditions other than malignant neoplasm) is inappropriate for this scenario. This code is intended for follow-up after treatment of a condition that has been resolved. Surveillance colonoscopy for a patient with a history of colon polyps is not considered a post-treatment follow-up in this sense.

Instead, Z86.0100 (Personal history of colon polyps, unspecified) is the appropriate code to reflect the reason for the procedure. Including Z09 in addition to the history code is typically incorrect unless the documentation clearly supports a true follow-up after completed treatment, which is uncommon for routine colon polyp surveillance.

You’ll also use K63.5 (Polyp of colon) to report that the physician found additional polyps during the procedure. You won’t report just K63.5 because the previous treatment and patient’s history of colon polyps are the reason for the procedure.

Sequencing: The code sequencing depends on the circumstances of the encounter. In a surveillance colonoscopy, the history code is usually listed first, followed by any findings such as K63.5. However, if a pathology report later shows a more specific diagnosis, such as adenomatous polyp of the descending colon, then you’ll assign the appropriate diagnosis code (in this case, D12.4 [Benign neoplasm of descending colon]).

For the anesthesia coding, you’ll append modifier PT (Colorectal cancer screening test; converted to diagnostic test or other procedure) when a colorectal cancer screening test is converted to a diagnostic or therapeutic procedure. This typically applies when the procedure begins as a screening colonoscopy. In cases involving surveillance due to a personal history of polyps, whether the procedure is treated as screening versus diagnostic can vary by payer. Therefore, applying modifier PT is not automatic and depends on how the payer classifies the service.

Some payers may want modifier 33 (Preventive services) appended to the applicable anesthesia code to indicate the sedation was used for a preventive service. However, according to the Medicare Claims Processing Manual, Chapter 18, you cannot use modifiers 33 and PT together. Of course, it’s best to double-check with your individual payer to confirm what modifiers they prefer.

Mike Shaughnessy, BA, CPC, Production Editor, AAPC