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Specialty billing Gastroenterology
Screening colonoscopies that turn diagnostic are where GI claims most often go wrong: the PT and 33 modifiers, the patient's cost-sharing and the code choice all change in the same procedure. If your practice bills a high volume of screening colonoscopies, EGDs and IBD infusions, small modifier errors add up. Our GI billing work is built to catch them before claims go out.
GI billing focus
The Core Problem
Modifier errors on screening-turned-diagnostic colonoscopies are a common, preventable cause of GI denials. A patient comes in for a routine screening colonoscopy, the physician finds and removes a polyp, and the claim now has to show both the screening intent and the therapeutic service. Bill it wrong and the claim can deny or the patient can be charged the wrong cost-share.
This isn't a training issue for your physicians. It's a coding and modifier logic issue, and it belongs with AAPC/CPC Certified Coders and Billers who check colonoscopy modifiers before claims reach a payer.
The Costliest Coding Decision
Modifier PT and modifier 33 are not interchangeable, and using the wrong one on a converted colonoscopy claim can lead to a denial or the wrong patient cost-sharing.
| Modifier | When it applies | Payer type |
|---|---|---|
| PT | Screening colonoscopy converts to diagnostic/therapeutic (e.g., polypectomy found) | Medicare |
| 33 | Preventive service with a USPSTF A or B rating; commercial plans use it to flag the screening intent. Medicare also uses 33 on moderate sedation (G0500/99153) that supports a screening colonoscopy | Commercial payers (check each plan's policy); Medicare for sedation |
The two modifiers exist because Medicare and commercial payers built different rules around the same clinical event. Applying commercial-payer logic (modifier 33) to a Medicare claim, or the reverse, can also put the wrong cost-share on the patient. For Medicare, when a screening colonoscopy turns therapeutic and PT is on the claim, the deductible is waived and coinsurance is 15% in 2026. Commercial plans follow federal preventive-services rules and their own policies. Getting this right the first time protects both your reimbursement and your patient relationships.
For Medicare dates of service in 2026, a screening colonoscopy that becomes therapeutic (billed with modifier PT) still has the deductible waived, and patient coinsurance is 15%. It drops to 10% for 2027–2029 and to zero from January 1, 2030.
Source: CMS Medicare Claims Processing Manual, ch. 18, §60.1 and MLN MM12656.
Correct Billing Workflow
Here's how a real conversion scenario runs through our coding workflow:
Patient presents for screening colonoscopy
Physician performs snare polypectomy during the exam
Modifier PT on the diagnostic or therapeutic code (for example 45385) signals "started as screening, became diagnostic or therapeutic". Medicare then waives the deductible and applies reduced coinsurance (15% for 2023–2026, 10% for 2027–2029, none from 2030)
For a commercial patient under a preventive mandate, the equivalent claim is coded with modifier 33 instead
Skip this step, or apply the wrong modifier, and the claim can deny, or pay incorrectly and put unexpected cost on the patient, generating a billing complaint back to your front desk.
IBD Biologics
MedixCode helps IBD practices manage the billing complexities of high-cost biologic infusions for Crohn's disease and ulcerative colitis. Our experts support:
We align documentation, drug administration, coding, and payer requirements to help reduce avoidable payment issues.
End-to-End Workflow
Claims move through the same six-step workflow before they reach a payer:
Ask about our IBD infusion billing workflow and how we manage modifiers PT and 33 on colonoscopy claims.
Book a Free ConsultationFrom your EHR/practice management system.
By coders experienced in gastroenterology procedures.
Colonoscopy, EGD and combination procedures checked against current NCCI edit pairs.
For biologics, imaging, and payer-required procedures.
Denials are worked by root cause, not written off.
Trust & Compliance
MedixCode is HIPAA compliant, and our staff are HIPAA-trained. For practices with an attached ASC, we handle both the professional (physician) and facility (ASC) billing sides under the same coding review.
Clear Pricing
Your fee is a share of net collections. Setup fees and monthly minimums don't apply, and we put the rate in writing once we know your physician and ASC volume. See how pricing works
Seamless Onboarding
Timing is a fair question when switching billing partners mid-year. Here's how the handoff runs:
Parallel run. We start alongside your current process before we take it over.
Patient-balance continuity. Existing patient balances and payment plans carry over to your statements and collections.
ASC + Physician-Side Handoff. Both billing sides transition on a coordinated timeline, not separately.
First-claim review. We audit your first claims against current payer rules before they go out, so errors are caught before they become a pattern.
FAQ
Answers on PT and 33, conversions, same-day EGD and colonoscopy, biologics and onboarding. More questions? See our FAQ
For Medicare, add modifier PT to the diagnostic or therapeutic colonoscopy code when a screening colonoscopy turns diagnostic or therapeutic. Commercial plans often use modifier 33 to show the service started as preventive screening, but policies vary by plan. Medicare also uses modifier 33 on moderate sedation that supports a screening colonoscopy.
You bill the diagnostic or therapeutic code for what was done, for example a snare polypectomy, with the conversion modifier the payer requires. For Medicare in 2026, the deductible is waived and the patient's coinsurance is 15%.
Yes. An EGD and a colonoscopy are different endoscopy families, so each is reported with its own code. Medicare pays the higher-valued procedure in full and reduces the other under its multiple-procedure rules. Modifier 59 or an X modifier is only needed when a specific NCCI edit applies and the documentation supports it.
We submit and track PA requests for infliximab, vedolizumab and similar biologics, including documenting any required step-therapy failures, before the infusion is scheduled.
No. It varies by payer mix and practice, so a blanket number wouldn't mean much. GI modifier scrubbing and NCCI checks before submission are core to how we work, and in the consultation we can go through your own colonoscopy and EGD claims with you.
Yes. We bill both the professional (physician) side and the facility (ASC) side for GI practices with an attached ASC, under the same coding review.
We do full GI coding review. Our AAPC/CPC Certified Coders and Billers review documentation, apply CPT codes and modifiers, and run NCCI and bundling checks before anything goes to a payer.
Your start date is set once we've reviewed your EHR/PM access, your payers and how your professional and facility claims are billed today. From there we plan the handoff with you, aiming to keep collections steady while you switch.
GI Billing · No Obligation
Talk to a GI billing specialist about your modifier logic, NCCI scrubbing, IBD infusion billing, and ASC billing needs. No commitment required.
Prefer email? Ask about your GI claims at info@medixcode.com.
