Gastroenterology Billing Services

Gastroenterology billing turns on one question: why was the procedure done? A colonoscopy done for screening is paid very differently from one done to investigate symptoms. A screening that finds and removes a polyp can change how the patient is billed mid-procedure. Patients notice these differences on their statements, which makes clean coding a patient-relations issue too.

Many GI groups also perform procedures in ambulatory surgery centers, where facility, physician, pathology, and anesthesia claims all run separately. Westmont Revenue Partners connects gastroenterology practices with vetted billing experts who understand gastroenterology billing, from endoscopy coding to payer rules for screening.

Who this is for

• Gastroenterologists and hepatologists
• GI groups that own or use an ambulatory surgery center
• Practices that perform endoscopy in hospital outpatient departments
• Multi-physician groups with in-house pathology or anesthesia
• Advanced endoscopy and inflammatory bowel disease practices
• Nurse practitioners and physician assistants in GI

What gets billed

• New and established patient office visits
• Screening colonoscopy for average-risk patients
• Screening colonoscopy for high-risk patients
• Diagnostic colonoscopy
• Colonoscopy with biopsy
• Colonoscopy with polyp removal by snare or forceps
• Diagnostic upper endoscopy (EGD)
• EGD with biopsy, polyp removal, or dilation
• Capsule endoscopy
• ASC facility fees for endoscopy
• Anesthesia services for endoscopy

Commonly billed codes

Code	Type	What it covers
45378	CPT	Diagnostic colonoscopy, with or without specimen collection
45380	CPT	Colonoscopy with biopsy
45381	CPT	Colonoscopy with injection under the lining
45384	CPT	Colonoscopy with removal of a lesion by hot biopsy forceps or bipolar cautery
45385	CPT	Colonoscopy with removal of a polyp using a snare
G0121	HCPCS	Medicare screening colonoscopy, patient not at high risk
G0105	HCPCS	Medicare screening colonoscopy, patient at high risk
43235	CPT	Diagnostic upper endoscopy (EGD)
43239	CPT	EGD with biopsy
43251	CPT	EGD with removal of a lesion using a snare
43248	CPT	EGD with guide wire and dilation of the esophagus
91110	CPT	Capsule endoscopy imaging the GI tract from the esophagus through the ileum
Z12.11	ICD-10-CM	Encounter for colon cancer screening
D12.6	ICD-10-CM	Benign colon polyp, unspecified

Note

Codes are examples for orientation, not a complete list, and do not guarantee coverage or payment. Always check current code sets and payer policy.

Billing challenges in gastroenterology

Screening versus diagnostic colonoscopy. Screening is done on a patient without symptoms to look for cancer. Diagnostic work is done because of symptoms, a prior finding, or a known problem. The reason decides the code, the diagnosis order, and patient cost-sharing. A biller reads the referral and note so intent is clear on the claim.

Screening that becomes diagnostic. When a polyp is removed during a screening, the claim reports the therapeutic code with the screening diagnosis and a finding code. Medicare uses modifier PT for this. Many commercial payers have their own approach. Medicare generally waives the deductible, but patient coinsurance may still apply, and the rules change over time. A biller applies each payer's current rule.

Follow-up colonoscopy after another test. A colonoscopy after a positive stool-based test may be treated differently from routine screening. Payer rules vary and have changed recently. A biller checks current payer policy before billing.

Multiple endoscopic codes in one session. Biopsy, snare removal, and other techniques at one site or several sites follow bundling rules. A biller reads the report to pick the highest-valued code per site and applies modifiers as needed.

EGD and colonoscopy on the same day. Two procedures in one session need correct sequencing and modifiers. A biller makes sure each is supported by its own findings and indication.

ASC claims. The ASC bills a facility fee, while the physician bills a professional fee. Place of service and payer contracts affect both. A biller keeps facility and professional claims consistent.

Anesthesia and pathology. Anesthesia and pathology often bill separately and add to what the patient owes. A biller coordinates diagnosis coding across all of them.

How Westmont can help

• Matching you with vetted billing experts experienced in gastroenterology and endoscopy
• End-to-end revenue cycle support for office, hospital, and ASC claims
• Denial management for screening, diagnostic, and bundling issues
• Credentialing support for new physicians and ASC enrollment
• Reporting that separates screening and diagnostic volume

Frequently asked questions

What is the difference between a screening and a diagnostic colonoscopy for billing?

A screening colonoscopy is for a patient with no symptoms and is billed with a screening diagnosis. A diagnostic colonoscopy is done because of symptoms, a prior abnormal result, or a known condition. The distinction affects the code, the diagnosis order, and the patient's cost-sharing. The referral and procedure note should make the reason clear.

What happens when a polyp is found during a screening?

The procedure may still be considered preventive, but the claim usually reports the therapeutic code, such as polyp removal, with the screening diagnosis. Medicare uses modifier PT for this situation. Medicare generally waives the deductible, though coinsurance may apply. Commercial payers differ, so check each payer's current rules.

Can I bill an EGD and a colonoscopy on the same day?

Yes, when both are medically necessary and documented. Each procedure needs its own indication and findings, and claims may need modifiers to show they are distinct. Some payers have specific edits for same-day endoscopy. A biller reviews the reports and payer policy before submitting.

How does billing differ in an ASC?

In an ASC, the facility bills a separate fee for its costs, and the physician bills for their own work. Anesthesia and pathology usually bill on their own claims. Place of service differs from the office or hospital, which affects payment. Ownership and contracts also matter, so confirm payer setup.

Why do endoscopy claims get denied?

Common causes include a diagnosis that does not match screening rules, frequency limits, missing modifiers, and bundled codes. Prior authorization requirements also vary by payer. A biller checks eligibility, frequency, and coding before the claim goes out and follows up on denials.

Is outsourcing gastroenterology billing a good fit?

It can be, especially for groups with high procedure volume or an ASC. Westmont does not submit claims itself. We connect you with vetted billing experts, and you decide whether a match is right for you.

Related billing services

• Colorectal Surgery Billing
• ASC Billing
• Anesthesia Billing
• Pathology Billing
• General Surgery Billing
• Internal Medicine Billing