CPT code 74455 – Voiding cystourethrogram

Key takeaways

CPT Code 74455 reports the radiological supervision and interpretation of a voiding cystourethrogram (VCUG). The contrast injection is billed separately with CPT 51600.

Bill 74455 globally when one entity owns the machine and reads the study. Split it into TC and modifier 26 when two entities bill.

A missing ICD-10 code that supports medical necessity is the leading denial trigger for 74455 claims.

Pabau’s claims management software submits and tracks 74455 claims through Claim.MD using the modifier and diagnosis codes your team enters.

CPT Code 74455: Official descriptor and procedure overview

CPT Code 74455 describes urethrocystography, voiding, radiological supervision and interpretation. The American Medical Association (AMA), which maintains the CPT code set, places 74455 in the Radiology section under Urinary Tract (74400-74485).

The study the code describes is a voiding cystourethrogram, often called VCUG. During a VCUG, contrast medium fills the bladder through a catheter and fluoroscopic images are taken during the filling phase and the voiding phase. As a result, the study shows bladder shape, urethral structure, and whether vesicoureteral reflux (VUR) is present.

What CPT 74455 covers and what it excludes

Specifically, CPT 74455 covers the radiologic supervision and interpretation (RS&I) part of the VCUG. In other words, it covers the fluoroscopic images taken during the voiding study and the written radiology report.

However, it does not cover the contrast injection into the bladder. Instead, that service is reported on its own under CPT 51600 (injection procedure for cystography). This applies when two entities perform the services or when the payer requires unbundling.

• Included in 74455: Fluoroscopic imaging during filling and voiding phases, image review, written radiology report with findings and impression, reading physician attestation
• Reportable on its own: CPT 51600 for catheter insertion and contrast injection, when not bundled with the RS&I
• Not billable on its own: Routine catheterization when it is part of the exam
• Not covered: Urodynamic studies, cystoscopy, or other diagnostic procedures done on the same date unless NCCI edits allow them to be billed on their own

CPT 74455 vs. 74450: How to choose the right code

CPT 74450 reports retrograde urethrocystography, radiological supervision and interpretation. In this study, contrast is injected backward through the urethral meatus, and the images show the urethra and bladder. By contrast, CPT 74455 images the same structures and also adds the voiding phase, captured as the patient empties the bladder.

The most frequent misassignment occurs when a provider performs a VCUG but selects 74450 because both codes image the urethra and bladder. So the voiding phase decides the code: if the patient voids during fluoroscopy, use 74455.

Modifiers for CPT Code 74455: TC, modifier 26, and global billing

CPT 74455 follows standard radiology modifier rules. As a result, three billing cases apply, each driven by who owns the machine and who reads the images.

A common error is billing 74455 globally when the practice does not own the fluoroscopy machine. For example, in a hospital outpatient department, the hospital bills its share on the UB-04 under OPPS, with no TC modifier. Meanwhile, the reading radiologist bills 74455-26 on the physician claim. Billing the code globally in that setting therefore results in a duplicate claim denial.

Medicare and payer reimbursement for CPT Code 74455

Medicare pays for CPT 74455 through the Medicare Physician Fee Schedule (MPFS), updated every year on January 1. However, rates vary by region and by billing case (global or split components). For reference, the table below shows the CY2026 national values from the CMS PPRRVU file. Dollar figures are total RVUs multiplied by the $33.4009 conversion factor, before regional adjustment.

The technical component carries about 85% of the global value, so the split decides who collects most of the payment.

The CMS PFS relative value files carry the work, practice expense and malpractice RVUs for 74455, updated each quarter. Qualifying APM participants are paid at the $33.5675 conversion factor instead, or $106.07 globally. Commercial payer rates also vary, and payers tend to set them as a share of the Medicare fee schedule. Although the exact figure depends on the contract, rates often range from 100% to 150%.

Medical necessity requirements and ICD-10 codes for CPT 74455

Payers require a supporting ICD-10-CM diagnosis code that establishes medical necessity. Without a code that maps to an accepted clinical reason, the claim fails medical necessity review. As a result, it is denied however well the study is coded.

Guidelines from the American Urological Association (AUA) and the American Academy of Pediatrics (AAP) name the main indications for a VCUG. Specifically, they are vesicoureteral reflux workup, recurrent urinary tract infections in children, and voiding dysfunction evaluation.

ICD-10-CM codes update every October, so verify codes against the current CMS ICD-10-CM tabular list before billing, mainly for VUR codes, where reflux nephropathy and hydroureter change the code.

Prior authorization requirements for CPT 74455

Prior authorization rules for CPT 74455 vary by payer, plan, and state. Medicare fee-for-service does not require prior authorization for VCUG as a standard rule, but Medicare Advantage plans may impose their own rules.

Confirm approval status before scheduling the study. Otherwise, an exam done without a required approval is denied, and that denial can be hard to overturn. Late approval depends on the payer, so ask early. Insurance eligibility verification done at scheduling also surfaces approval rules before the patient arrives.

• Medicare fee-for-service: Mostly no prior auth required for VCUG
• Medicare Advantage: Check each plan’s rules; many plans require PA for scans
• Commercial insurers: Many commercial payers apply scan PA rules, so check each payer’s list
• Medicaid: Varies by state; pediatric VCUG for VUR workup is often covered without PA under AAP guidelines, but confirm by state

A prior authorization request for 74455 should include the referring provider’s note on the clinical indication and any earlier scans. Also add the ICD-10 code that supports medical necessity. After that, most payers process standard PA requests within 3-5 business days.

Documentation requirements to support CPT Code 74455 claims

The radiology report for a 74455 claim must contain key elements to survive payer audit. If any element is missing, the payer has grounds for recoupment on post-payment review, not just initial denial.

The medical billing workflow starts with this report, so the claim can only prove what the records show.

• Clinical indication: The reason for the study must appear in both the ordering provider’s notes and the radiology report. A vague reason such as “evaluate urinary tract” is not enough, because the recorded reason must match the ICD-10 code on the claim.
• Technique description: The report must state that fluoroscopic images were taken during the voiding phase. Without it, the study could pass for a cystogram only, which is another code.
• Fluoroscopic images taken: Document the number of spot images or sequences taken, since this shows that real-time fluoroscopy, not just static plain films, was done.
• Findings section: Describe the bladder morphology, presence or absence of VUR, and urethral appearance during voiding. Grade VUR if identified.
• Impression: The reading doctor must state a conclusion that directly addresses the clinical question.
• Physician attestation: The radiologist or reading doctor must sign the report. An unsigned or incomplete report therefore cannot support a 74455 modifier 26 claim.

On a radiology study like 74455, a clean claim lines up three elements one to one. Specifically, they are the service done, the fluoroscopy method recorded, and the ICD-10 indication on the claim.

How the VCUG procedure is performed: A clinical overview for coders

Knowing the physical sequence of a VCUG helps coders apply CPT 74455 correctly. It also shows when a companion code like CPT 51600 is billable with it.

1. Catheter placement: First, a urethral catheter is inserted under sterile conditions. However, this is not billable on its own as routine catheterization when it is part of the exam.
2. Contrast instillation (CPT 51600): Next, contrast medium is injected through the catheter to fill the bladder. The injection may be reported on its own under CPT 51600 when the radiology team performs it and the payer does not bundle it.
3. Filling-phase fluoroscopy: Then, fluoroscopic images are taken as the bladder fills. During this step, the fluoroscopist checks bladder wall contour, trabeculation, and ureterovesical junction reflux during filling.
4. Voiding-phase fluoroscopy: Afterward, the patient voids under continuous fluoroscopic monitoring. This is the key phase that sets 74455 apart from other urinary tract imaging codes. Also, VUR is graded during this phase.
5. Post-void image: Finally, a last image is taken to check for leftover contrast and how fully the bladder empties.
6. Report generation: Lastly, the reading doctor reviews all fluoroscopic sequences and dictates a signed report. This report is the RS&I part that 74455 covers.

Can CPT 74455 be billed with urodynamics codes?

Yes, CPT 74455 can sometimes be billed with urodynamics codes on the same date of service. However, NCCI edits decide whether separate billing is allowed or a modifier override applies.

The urodynamics studies most often done with it are CPT 51726 (complex cystometrogram), 51728 (CMG with voiding pressure studies), and 51736 (simple uroflowmetry). Each code pair has its own edit status in the current CMS NCCI tables, so before billing 74455 with any urodynamics code, verify the edit status directly in the AAPC CPT code lookup or CMS NCCI tool.

• 74455 + 51736 (uroflowmetry): This pair may carry a bundling edit, so check the current NCCI table before billing both. Where an edit allows a modifier, modifier 59 applies only when the procedures were clinically distinct and documented on their own.
• 74455 + 51726 or 51728 (cystometrogram): These pairs may also carry bundling edits. Modifier 59 needs the clinical reason for doing both a urodynamic study and a VCUG at the same visit. So document it clearly in the medical record.
• Documentation requirement: When modifier 59 overrides an NCCI edit, the record must show the procedures were distinct services. Specifically, they need distinct times or distinct clinical purposes within the same encounter.

NCCI edit tables update every quarter, so confirm the current edit status before billing any CPT 74455 and urodynamics combination. After all, an edit that permitted separate billing last quarter may have changed.

Common claim denial reasons for CPT 74455 and how to prevent them

Most 74455 denials fall into a small number of repeat patterns. Find the denial reason on the Explanation of Benefits (EOB), then match it to the fix below. Doing so resolves most rejections on first appeal.

A denial management workflow built around these patterns keeps a radiology or urology billing team ahead of the problem rather than reacting to remittances. Likewise, reviewing common denial codes with the CARC codes on your 835 remittances sorts each issue into code selection, records or approval.

Because many of these issues start at the front end, a pre-submission check for missing or invalid claim details catches them early. Reading each electronic remittance advice file, instead of only posting the payment, shows denial patterns that point to a record-keeping or workflow problem.

How claims management software reduces denials for CPT 74455

Many urology and radiology teams check coverage on a payer portal, key the claim into an outside clearinghouse and post the remittance by hand. As a result, each handoff is a chance for a -26 modifier or an N13.71 code to drop off the claim.

Pabau, the practice management platform we build, runs that cycle in one system. Its claims software for radiologists checks eligibility through Claim.MD before the visit. It then submits and tracks claims using the modifier and diagnosis codes your team enters.

Claim validation checks each claim for missing or invalid details before it leaves Pabau. When a payer rejects a claim, Pabau flags it with a link to the field that needs correcting. Payments then settle straight from electronic remittance advice (ERA) files.

Submit and track CPT 74455 claims in one place

Pabau checks eligibility through Claim.MD before the visit, then submits and tracks 74455 claims using the modifier and diagnosis codes your team enters. Rejected claims come back flagged with the field to fix.

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Conclusion

CPT Code 74455 rarely fails on the code itself. Instead, it fails when the modifier doesn’t match the place of service, when the diagnosis doesn’t support the study, or when the plan wanted approval first.

Build those three checks into scheduling and report sign-off, before the claim leaves the practice. The urodynamics pairing is the one judgment call left, and the current NCCI table settles it each quarter.

Book a demo to see how Pabau submits and tracks urology and radiology claims through Claim.MD.

Continue your research

Need to understand how your clearinghouse processes 74455 claims? Claim.MD clearinghouse overview explains how electronic claim routing, real-time eligibility, and ERA posting work together.

Struggling with claim submission errors across your radiology billing? Medical billing compliance guide covers documentation standards, payer requirements, and audit readiness.

Want to see the 837 file structure behind your electronic claims? 837 file format explained breaks down the transaction set that carries 74455 claims to payers.

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