Gastroenterology billing

When a screening finds a polyp: who pays in 2026

A Medicare screening with nothing removed has no deductible or coinsurance. When a polyp is removed or a biopsy taken, you bill the diagnostic code with PT, and under chapter 18 of the Medicare Claims Processing Manual the deductible stays waived and coinsurance is 15 percent through 2026, 10 percent from 2027 through 2029, and zero from 2030. Without PT, the patient owes the deductible and full coinsurance.

Most commercial plans (all but those grandfathered from March 2010) cannot charge cost sharing for polyp removal during a screening, or for the consultation, prep, anesthesia and pathology with it, per the Departments of Labor, HHS and Treasury. The AGA’s coding guide puts 33 on each code. Our patient billing team explains any balance left.

Colonoscopy after a positive stool or blood test

Medicare counts a colonoscopy after a positive stool-based test (such as FIT or Cologuard) as part of the screening, and since January 1, 2025 a positive blood-based test qualifies too, under 42 CFR 410.37(k). Bill the screening code with KX.

Those commercial plans must cover the follow-up colonoscopy after a positive stool-based test without cost sharing. The USPSTF has not recommended blood-based tests, so commercial coverage of those varies. The screening diagnosis (Z12.11 for the colon) goes first, and many payers want specific history codes, such as Z86.0101 for adenomatous and serrated polyps.

Anesthesia, sedation and where the scope is done

Medicare anesthesia for a screening colonoscopy is 00812, with no deductible or coinsurance; once it turns diagnostic it is 00811 with PT. Moderate sedation by the endoscopist is G0500 for Medicare (99152 for commercial), plus 99153 for added time, with 33 on a screening and, for Medicare, PT once it turns diagnostic.

In the office (place of service 11), Medicare pays one rate covering the physician, staff and equipment. In an ASC (24) or hospital outpatient department (22 or 19), the physician’s rate covers only the physician’s share and the facility bills its own fee. For 2026, the fee schedule final rule cut work RVUs for most procedures by a 2.5 percent efficiency adjustment and gave office settings more indirect practice expense than facilities.

Biopsy, polypectomy and same-day scopes

A biopsy and snare of the same polyp is the snare code alone. Under chapter VI of the 2026 NCCI manual, the edit between 45385 and 45380 is bypassed with 59 or XS only for separate lesions. Control of bleeding and fluoroscopy are part of the scope, and an EGD with biopsy (43239) includes the diagnostic EGD and washings.

Medicare pays two codes from one family, such as 45385 and 45380, under the special endoscopy rule in chapter 12 of the claims manual: the higher code in full plus the difference between the other and the base (45378). An EGD and a colonoscopy the same day get the usual multiple-procedure reduction. An E/M on the scope day needs a separately identifiable reason and modifier 25. An interrupted colonoscopy is billed with 53, at about half its value.

Prior authorization and why GI claims deny

Medicare Advantage, Medicaid and commercial plans keep their own authorization lists, so we check when the procedure is scheduled. Since January 1, 2026, the CMS prior authorization rule gives Medicare Advantage, Medicaid and CHIP 7 calendar days for standard requests and 72 hours for urgent ones, with a specific reason for any denial. Drugs, such as IBD biologics, are outside it.

Common GI denials and cost-sharing errors, with the reason codes that often carry them (codes vary by payer):

• A screening inside the frequency limit, or a follow-on scope without KX (CO-119)
• PT or 33 missing, so the patient is charged a deductible or coinsurance (PR-1 or PR-2)
• Biopsy and snare billed together without 59 or XS (CO-236)
• Screening diagnosis not listed first, or a history code too vague (CO-11)
• An E/M on the procedure day without modifier 25 (CO-97)
• No authorization on file where the plan requires one (CO-197)

Each goes through our denial management process, and our eligibility checks confirm screening coverage, frequency and authorization before the procedure.

Credentialing for gastroenterology

GI groups usually enroll in three places: every gastroenterologist, PA, NP and CRNA who bills; the endoscopy center or ASC, which bills its own facility fee; and the hospitals where you hold privileges. Our provider credentialing service handles Medicare (PECOS), Medicaid and commercial applications at $189 per payer application, less in bulk.