What makes gastroenterology billing services different
Gastroenterology billing services deal with a distinction no other specialty bills quite the same way: the screening colonoscopy that turns diagnostic the moment a polyp is found. That single change affects the procedure code, the diagnosis coding, the anesthesia billing and the patient's cost share. Add endoscopic retrograde cholangiopancreatography, capsule studies, liver clinic E/M work and infusion suites billing biologics, and GI practices run several billing models under one roof. Fastora's certified billing and coding professionals handle these claims for gastroenterology practices as part of our wider medical billing services.
Much of a GI practice's revenue rides on procedures done in the office endoscopy suite or an ambulatory surgery center. Site-of-service rules, anesthesia billing and prior authorization for advanced procedures decide whether those high-value claims pay cleanly or stall for months.
Screening vs diagnostic colonoscopy billing
A screening colonoscopy is reported with a screening code such as G0121 for Medicare, while a colonoscopy that finds and removes a polyp becomes diagnostic and is reported with the therapeutic procedure code, such as 45385. Modifiers PT or 33 flag that the procedure began as screening so cost-sharing rules apply correctly.
The operative report has to support the change: the indication, what was found, what was removed and how. When anesthesia is provided, the anesthesia claim must match the procedure and the screening-or-diagnostic status. We reconcile all three — procedure, diagnosis and anesthesia — before submission.
Prior authorization and site of service
Advanced procedures such as ERCP, endoscopic ultrasound, capsule endoscopy and biologic infusions often need prior authorization from commercial and Medicare Advantage plans. The approval should list the procedure codes and the site of service, because office, ASC and hospital outpatient departments pay under different rules.
Infusion drugs add another layer: buy-and-bill under the medical benefit versus specialty pharmacy under the pharmacy benefit changes who bills the drug and which authorization path applies. We confirm the benefit and the authorization before the infusion is scheduled, not after it denies.
Gastroenterology coding: key codes and modifiers
| Code | Descriptor (summary) | Billing note |
|---|---|---|
| 45378 | Colonoscopy, flexible, diagnostic | Screening becomes diagnostic when a polyp is removed |
| 45380 | Colonoscopy with biopsy, single or multiple | Biopsy method in the report |
| 45385 | Colonoscopy with removal of polyp by snare | One code per session regardless of polyp count |
| 43235 | Upper GI endoscopy, diagnostic | EGD and colonoscopy same day need distinct-service support |
| 43239 | Upper GI endoscopy with biopsy | Biopsy documented in the report |
| 43260 | ERCP, diagnostic | Therapeutic ERCP uses intervention-specific codes |
| G0121 | Colorectal cancer screening, colonoscopy | Medicare screening code; PT modifier if it turns diagnostic |
When a screening colonoscopy becomes therapeutic, diagnosis coding must carry both the screening indication and the finding. Modifier 33 or PT tells the payer the procedure began as screening so patient cost share is handled under preventive rules. Our medical coding team reviews GI procedure notes against the billed codes before claims go out.
Multiple procedures on the same day — for example EGD with colonoscopy — need distinct-procedure modifiers supported by separate indications and findings in the report. Sedation billed by the endoscopist follows different rules than anesthesia billed by a separate provider.
Infusion and biologic drug billing
Biologics for inflammatory bowel disease are billed with J codes for the drug and infusion codes for the administration. The drug claim needs the correct units — milligrams or the billing unit the code describes — and the administration claim needs the infusion time and method.
Some payers require step therapy or site-of-care redirection to a home infusion or hospital outpatient setting, which changes both the authorization and the billing. We track each payer's infusion policy so the claim matches the site where the drug was actually given.
Common gastroenterology billing denials and how we prevent them
| Denial | Typical cause | Prevention step |
|---|---|---|
| Screening billed as diagnostic | Polyp removal not reflected in code and modifiers | Procedure, diagnosis and modifiers reconciled to the report |
| Anesthesia denied | Anesthesia claim mismatched to procedure status | Anesthesia matched to the screening or diagnostic code |
| Authorization missing | Advanced procedure or infusion done without approval | Auth confirmed for codes and site before scheduling |
| Bundled EGD and colonoscopy | Two endoscopies billed without distinct-service support | Separate indications documented for same-day procedures |
| Infusion units denied | Drug units mismatched to the J code's billing unit | Units calculated from dose against the code descriptor |
Every claim passes our Advanced Pre-Submission Claim Review before submission. Denials that still occur are worked by our denial management team, which corrects and resubmits or appeals with the record, and open balances are followed up by payer and age.
Credentialing for gastroenterologists
Gastroenterologists, advanced endoscopists and nurse practitioners each need enrollment with the plans they bill, and new physicians need to be linked to the group before procedural claims pay in network. ASC and hospital outpatient billing may involve separate facility enrollment.
Our credentialing and enrollment service tracks each file through a nine-stage process, from document collection and NPI and CAQH setup to payer applications, follow-ups and final approval.
How Fastora supports gastroenterology billing
Fastora works inside your existing EHR/PM system under the user access you grant, with no software to install and no hidden setup fees. You get a dedicated account contact, transparent dashboards, monthly performance reporting and a monthly review call.
Fees are quoted after a free assessment. To see how your current claims hold up, start with a free billing assessment.
Gastroenterology billing and coding
Gastroenterology billing and coding covers office visits, endoscopy and colonoscopy procedures, pathology coordination, and anesthesia billing when cases go to the ASC. Gastroenterology medical billing means matching the procedure note to the code — screening versus diagnostic colonoscopy, polyp removal method, and the modifiers payers require — and tracking the prior authorizations many plans now require for elective endoscopy. Coding lag is the classic GI leak: procedures done but not coded for days, which delays the whole claim. Our medical coding service keeps GI procedures coded to the note.
Choosing a gastroenterology billing company
A gastroenterology billing company should show procedure-level workflows: how endoscopy claims are coded and submitted, how anesthesia and pathology are coordinated, and how screening-colonoscopy denials are worked. Ask for the turnaround from procedure date to claim submission — in GI, that number tells you more than any marketing claim. Our prior authorization service handles elective-procedure authorizations and a free medical billing audit shows where your GI claims stall.