CPT code 74328 – Biliary duct endoscopic catheterization

Key Takeaways

CPT code 74328 covers endoscopic catheterization of the biliary duct only – pancreatic duct cannulation uses 74329, and both ducts together use 74330.

Only the interpreting radiologist bills 74328 for the supervision and interpretation component; the performing gastroenterologist bills the ERCP procedure code separately.

Documentation must include fluoroscopic images, a signed interpretation report, physician attestation, and a supported ICD-10 diagnosis before the claim is submitted.

Pabau’s claims management software tracks required documentation and routes 74328 claims through electronic submission with real-time denial alerts.

CPT code 74328: Official descriptor and procedure overview

CPT code 74328 is defined by the American Medical Association (AMA) as: Endoscopic catheterization of biliary duct with radiological supervision and interpretation. It sits within the 74320-74330 diagnostic radiology code family, which covers the imaging supervision components of biliary and pancreatic endoscopic procedures.

The key phrase here is “supervision and interpretation.” This code does not describe the endoscopy itself. It describes the radiologist’s work of guiding fluoroscopic imaging and producing a written interpretation report. The gastroenterologist performing the ERCP bills the procedural component under a separate GI endoscopy code (such as 43264 or 43275).

What CPT 74328 covers and what it excludes

CPT code 74328 covers selective cannulation of the common bile duct under fluoroscopic guidance, contrast injection, fluoroscopic imaging, and the physician’s written interpretation of those images. All four elements must occur for the code to be billable. If the physician performs fluoroscopy but does not produce a signed report, the S&I component is not separately billable.

What the code does not include is equally important for accurate medical billing workflows:

• Pancreatic duct cannulation: Covered by 74329, not 74328. If only the pancreatic duct is entered, 74329 applies.
• Combined biliary and pancreatic cannulation: Covered by 74330. Billing both 74328 and 74329 for a combined procedure is incorrect – use 74330 alone.
• The endoscopic procedure itself: ERCP procedural codes (43264, 43275, 43276, etc.) are billed by the gastroenterologist. 74328 is strictly the radiologist’s imaging S&I component.
• Diagnostic cholangiography during open surgery: That falls under 47500 or 47505, not the ERCP imaging family.

CPT 74328 vs 74329 vs 74330: Choosing the right code

The correct code depends entirely on which duct (or ducts) the operative note documents as selectively catheterized. Coders should read the report before billing, not assume.

When the operative note is ambiguous – for example, the physician mentions “biliary and pancreatic anatomy visualized” without specifying selective cannulation of each – query the physician before coding. Failed or incomplete cannulation does not support billing any of these three codes.

How the procedure is documented for billing

Accurate documentation is what separates a paid 74328 claim from a denied one. Payers audit four specific elements, and a missing element in any one of them triggers a denial.

1. Indication: The clinical reason for the procedure, supported by an ICD-10 diagnosis that meets medical necessity criteria for the applicable Local Coverage Determination (LCD).
2. Fluoroscopic images: Stored images (not just a note that fluoroscopy was used) demonstrating catheterization of the biliary duct with contrast.
3. Signed interpretation report: A separate written report authored by the interpreting radiologist, distinct from the gastroenterologist’s procedure note. This report is what justifies billing the S&I component.
4. Physician attestation: The radiologist must personally supervise or perform the imaging and sign the interpretation. A technician’s worksheet is not sufficient.

Many payers also require that the interpretation report reference specific findings from the fluoroscopic images, not generic language like “contrast was injected.” The stronger the documentation, the lower the audit and denial risk.

Supervision and interpretation billing: Who bills CPT 74328?

CPT code 74328 is billed by the radiologist who supervises fluoroscopic guidance and produces the written interpretation report – not the gastroenterologist who performs the endoscopy. This split-specialty billing is a frequent source of compliance errors.

Under AMA CPT supervision and interpretation (S&I) rules, the two physicians each bill their respective component separately:

• Gastroenterologist: Bills the ERCP procedural code (e.g., 43264 for ERCP with removal of calculus, or 43275 for removal of foreign body/stent).
• Radiologist: Bills CPT code 74328 for the fluoroscopic S&I component, provided they produce and sign an independent interpretation report.

When the same physician performs both the endoscopy and reads the fluoroscopy images, that physician may bill both codes – but this is uncommon in practice. In hospital outpatient settings, the radiologist is typically a separate physician employed by the radiology group. In an ASC or independent GI center, the billing arrangement should be confirmed with the facility’s compliance officer before submission.

Modifier 26 (professional component) is generally not needed with 74328 in a global arrangement, but confirm with your MAC if there is any question about component billing in your jurisdiction.

ICD-10 codes commonly linked to CPT 74328

Every 74328 claim must carry an ICD-10-CM diagnosis code that documents the medical necessity for the biliary endoscopy procedure. The diagnosis must align with the applicable MAC Local Coverage Determination.

These diagnoses are consistent with standard ERCP indications and are cross-referenced against MAC LCDs. Always verify the specific diagnoses covered under your jurisdiction’s LCD before submitting, as covered diagnoses vary by region and payer. Submitting 74328 against a non-covered diagnosis is a primary denial trigger.

Medicare coverage, reimbursement, and RVU values for CPT 74328

Medicare covers CPT code 74328 when performed for a medically necessary indication documented in the medical record and supported by a diagnosis covered under the applicable LCD. Centers for Medicare and Medicaid Services (CMS) sets reimbursement rates annually through the Medicare Physician Fee Schedule (MPFS). Exact payment amounts vary by geographic adjustment factor (GPCI), so the figures below represent national non-facility averages. Use the CMS Physician Fee Schedule lookup tool and the FastRVU lookup for current year-specific figures by locality.

Radiologists billing 74328 through claims management software can automate fee schedule comparisons and flag when payer-allowed amounts fall below the Medicare floor, prompting timely appeals. Submitting claims electronically through electronic claims via Claim.MD gives practices real-time eligibility verification and ERA remittance data, which is especially useful when tracking 74328 reimbursement across multiple payer contracts.

Commercial payer rates for 74328 vary significantly. Some plans pay a percentage of Medicare (typically 100-130%), while others use fee schedules negotiated through hospital contracts. Tracking revenue cycle management data at the code level helps radiology practices identify when a payer’s reimbursement for 74328 warrants renegotiation.

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Prior authorization and common CPT code 74328 denial reasons

Prior authorization

Medicare fee-for-service does not currently require prior authorization for CPT code 74328 in most settings, but Medicare Advantage plans, commercial insurers, and Medicaid managed care organizations commonly do. Requirements vary by payer and plan. Confirm prior auth requirements before the procedure whenever the payer is a Medicare Advantage, Medicaid managed care, or commercial plan – a missing authorization is a leading denial cause and is not easily appealed after the fact.

When prior auth is required, submit the following documentation: Clinical indication, supporting ICD-10 diagnosis, physician order, relevant imaging history, and operative plan. CMS has expanded prior authorization requirements for certain outpatient imaging services under hospital outpatient prospective payment – verify with your MAC whether 74328 falls within the current list for your setting.

Common CPT code 74328 denial reasons

Structured denial management workflows catch these patterns before they recur. Tracking denial reasons by code at the practice level reveals whether the issue is documentation, coding, or payer policy – each requires a different fix. For billing teams that need a quick reference on what denial codes mean, the denial codes in medical billing reference covers CARC/RARC codes that commonly accompany 74328 rejections.

CCI edits and bundling rules: What cannot be billed with 74328

The CMS Correct Coding Initiative (CCI) edit tables determine which codes are considered components of another and therefore cannot be billed separately without a modifier override. For CPT code 74328, the most significant bundling relationships involve the GI ERCP procedural codes.

CCI edits for the ERCP family are updated quarterly. The relationships below reflect standard coding guidance and should be verified against the current CMS CCI table before submission. Overstating modifier applicability constitutes improper billing – confirm with your MAC before using modifier 59 or XS to override an edit.

The key distinction for the 43264/74328 pairing is who billed what. When the gastroenterologist bills 43264 and a separate radiologist bills 74328 for the independent fluoroscopic interpretation, payers generally accept both claims – provided both physicians submit separate interpretation reports. When a single physician attempts to bill both, the edit applies and the S&I code will be denied. Good clean claim submission practices mean resolving these bundling questions before the claim leaves the practice, not after a denial arrives. For practices needing broader context on billing compliance obligations, medical billing compliance guidelines apply to CCI modifier use as much as to any other billing practice.

Conclusion

Getting CPT code 74328 paid consistently comes down to three things: The right code (74328 vs 74329 vs 74330, based on the operative note), the right biller (the interpreting radiologist, not the performing gastroenterologist), and the right documentation (a signed interpretation report, stored fluoroscopic images, and a covered ICD-10 diagnosis).

Pabau’s claims management software supports documentation checklists, electronic claim routing, and denial tracking across the ERCP billing workflow. To see how it handles radiology and GI billing at your practice, book a demo.

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Confused about what claim denial codes mean? Denial codes in medical billing explains the CARC and RARC codes that accompany denied 74328 and ERCP claims.

Looking for an overview of ERCP and GI billing? AAPC Codify CPT lookup lets you search the full 74320-74330 biliary endoscopy code family with descriptor detail and crosswalk data.

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