HCPCS Code G0235: PET imaging, any site, not otherwise specified

Key takeaways

HCPCS Code G0235 is the Level II G-code for PET imaging at any site not otherwise specified by a more specific code.

CMS assigns G0235 coverage status M, non-covered by Medicare, so it reports PET studies Medicare has already declined to pay for.

The umbrella NCD 220.6 was retired on January 1, 2022. Oncologic FDG-PET coverage now sits under NCD 220.6.17.

PET uses outside a surviving sub-determination fall to your Medicare Administrative Contractor, so read its local article before billing.

Practice management software like Pabau keeps the order, the clinical note, and signed patient forms on one record.

Most coding references treat HCPCS Code G0235 as a PET code you bill and then defend. CMS treats it as something else entirely. The July 2026 alpha-numeric HCPCS file gives G0235 coverage status M, non-covered by Medicare. Its pricing indicator is 00, so Part B does not price it separately. Those two flags change the coder’s job. G0235 is not a payment code you argue for. It is the code CMS tells you to report when a PET study falls outside covered indications.

This guide covers what the descriptor means and why the retirement of NCD 220.6 reshaped PET coverage. It also sets out which sub-determinations survived, plus the ICD-10 and modifier rules that apply. Then it covers the documentation to keep, and how patient liability works when the indication is not covered.

HCPCS Code G0235: definition and clinical description

HCPCS Code G0235 is a Level II Healthcare Common Procedure Coding System code maintained by the Centers for Medicare and Medicaid Services (CMS). Its official long descriptor is: PET imaging, any site, not otherwise specified.

The “not otherwise specified” (NOS) designation defines the code’s role. It applies when a positron emission tomography scan does not match any more specific PET code. That can be because of the body site imaged, or because of the clinical indication. In practice that is rare, because the CPT nuclear medicine codes cover almost every PET study performed today.

Positron emission tomography uses radioactive tracers to image metabolic activity, most often with fluorodeoxyglucose (FDG). Covered PET services are billed with CPT codes, not G-codes. Those are 78429 through 78434, 78459, 78491, 78492, 78608, and 78811 through 78816, each reported alongside a tracer code such as A9552 for FDG.

Only three PET G-codes remain in the HCPCS file, and none of them is a preferred covered alternative. G0219 reports whole-body melanoma PET for non-covered indications. G0252 reports full and partial-ring PET for the initial diagnosis of breast cancer or breast surgical planning. G0235 covers everything else that Medicare does not pay for.

G0235 code details at a glance

The table below summarizes the administrative and coverage fields attached to HCPCS Code G0235. Every value comes from the CMS July 2026 alpha-numeric HCPCS file.

Medicare coverage for HCPCS Code G0235

Medicare does not cover G0235. The code carries coverage status M in the HCPCS file, and the CMS coding guidance for PET instructs providers to bill G0235 for non-covered indications. So a G0235 line is not a claim you expect to be paid. It is a claim you expect to be denied, on purpose, so the charge can move to the patient or a secondary payer.

That is easy to miss, because the coverage landscape it sits inside changed substantially. Older guides still describe a single national policy for PET. There is no longer one.

NCD 220.6 was retired on January 1, 2022

CMS removed the umbrella national coverage determination for PET scans effective January 1, 2022. The Medicare Coverage Database entry is now titled NCD – Positron Emission Tomography (PET) Scans – RETIRED (220.6). In its place sit a handful of separately numbered sub-determinations, each covering one clinical use.

These are the sub-determinations still in force:

• NCD 220.6.1, PET for perfusion of the heart. Billed with CPT 78491 or 78492, using rubidium-82 (A9555) or nitrogen-13 ammonia (A9526) as the tracer.
• NCD 220.6.8, FDG PET for myocardial viability. Billed with CPT 78459 for a single study, or 78429 when a CT is acquired concurrently. Combined perfusion and viability studies use 78432 or 78433.
• NCD 220.6.9, FDG PET for refractory seizures. Covered only for pre-surgical localization of the seizure focus, using CPT 78608 with tracer A9552.
• NCD 220.6.13, FDG PET for dementia and neurodegenerative disease. Covered for the differential diagnosis of frontotemporal dementia and Alzheimer’s disease, again with CPT 78608.
• NCD 220.6.17, FDG PET for oncologic conditions. This replaced fourteen separate cancer-specific NCDs. Billed with CPT 78811 through 78816 and modifier PI or PS.
• NCD 220.6.19, NaF-18 PET to identify bone metastasis. This reverted to national non-coverage, so sodium fluoride PET is not payable.

One more policy left the manual after that. CMS removed NCD 220.6.20 for beta amyloid PET effective October 13, 2023. Amyloid imaging in dementia is now a contractor decision as well.

Where local contractor discretion applies

Any PET use not named in the sub-determinations above may be covered at local MAC discretion under section 1862(a)(1)(A) of the Social Security Act. That is the rule CMS wrote when it retired the umbrella NCD, and it is where G0235 lives. Your MAC decides, and its decision is published in its own coverage material rather than in the national manual.

Look up the article titled “Billing and Coding: Positron Emission Tomography Scans” for your jurisdiction in the CMS Medicare Coverage Database. It carries the covered diagnosis lists, the tracer pairings, and the modifier requirements your claims will actually be adjudicated against.

Coverage with evidence development no longer applies

Older PET guidance describes a registry requirement, where scans were paid only inside an approved study. That requirement is long gone. CMS ended coverage with evidence development for oncologic FDG-PET on June 11, 2013, and ended it for beta amyloid PET in October 2023.

Clinical trial modifiers still exist, but for a narrower reason. Append Q0 for an investigational service furnished in an approved clinical research study, or Q1 for a routine service in the same setting. Neither modifier turns a non-covered indication into a covered one.

ICD-10 codes to use with G0235

The ICD-10-CM code on a PET claim decides which PET code you should be using in the first place. If the documented diagnosis appears on your MAC’s covered list, the study is billed with a CPT PET code and G0235 is the wrong choice. G0235 is what you report when the diagnosis is not on that list.

The table below shows the common PET indications, the diagnosis codes that support them, and where coverage actually sits for each one.

Two pairings trip coders up regularly. The first is epilepsy. NCD 220.6.9 lists a specific set of epilepsy codes, most of them intractable forms. An unspecified code such as G40.909 will not support a pre-surgical PET study. The second is melanoma history. Z85.828 covers other malignant skin neoplasms and explicitly excludes melanoma, so Z85.820 is the correct code for melanoma restaging.

When the documented indication is genuinely outside every covered list, the diagnosis still belongs on the G0235 line. It is what tells the payer, the patient, and any later auditor why the scan was performed.

HCPCS Code G0235 billing guidelines

Billing G0235 correctly means proving to yourself that no covered pathway exists before you file it. Practices that run on practice management software with integrated records can check the order and the note in one place. That beats chasing paperwork across systems.

The steps below reflect standard requirements under Medicare. Commercial payer and Medicare Advantage rules differ.

1. Identify the CPT PET code that describes the study. Start from the extent of the scan and whether a CT was acquired concurrently. Almost every modern PET study maps to a CPT code, which is the first sign that G0235 may not be needed.
2. Check the indication against the surviving sub-determinations. If it is covered, bill the CPT code with the correct tracer and modifier. Assigning G0235 to a covered indication converts a payable claim into a denial.
3. Check your MAC’s PET article for local discretion. Uses outside the national sub-determinations may still be covered in your jurisdiction. The MAC article is the only place that tells you.
4. Issue an ABN before the scan. Coverage status M means the beneficiary needs to know in advance that they may be liable. Record the signed notice against the patient’s file, not in a separate folder.
5. Report the tracer on its own line. FDG is A9552, nitrogen-13 ammonia is A9526, and rubidium-82 is A9555. A missing tracer line is a routine cause of rejected PET claims.
6. Document place of service accurately. PET is usually performed in a hospital outpatient department (POS 22) or an independent imaging center (POS 11 or POS 49). Confirm the code matches where the scan actually happened.
7. Submit on the right form. Hospital outpatient services use the UB-04 (CMS-1450). Professional component billing uses the CMS-1500.

Modifiers used with G0235 and PET claims

The modifier decides who pays when a PET claim is denied, so it carries more weight on a G0235 line than on most codes. The table below sets out the modifiers that appear on PET claims and what each one signals.

Note what is missing from that list. There is no modifier that makes G0235 payable. The choice in front of you is only ever whether the patient can be billed.

Documentation requirements for G0235

A G0235 line invites a records request, because it names an indication the payer has no covered pathway for. The record needs to answer two questions without help: why the scan was performed, and why no more specific code applied.

Keep the following against the patient record:

• The signed order from the treating physician, naming the clinical indication
• A short note explaining why no covered PET pathway or CPT code fit the study
• The tracer used and the administered dose, matching the tracer line on the claim
• The anatomic extent of the scan, and whether a CT was acquired concurrently
• The radiologist’s interpretation and report
• The signed Advance Beneficiary Notice, dated before the appointment
• Any prior imaging or pathology the ordering physician relied on, held with the patient’s other secure patient records

Dementia studies carry a longer list. For a PET scan under NCD 220.6.13, CMS expects more. The record must show the date of symptom onset and the clinical syndrome diagnosed. It must also carry a Mini Mental State Examination score and the presumptive cause. It also expects any neuropsychological testing, the results of structural imaging, relevant laboratory results, and the patient’s current medications.

Practices handling this volume benefit from EHR integration that carries the order and the clinical note into the same record the billing team works from. That removes the manual re-entry step where indications and codes drift apart.

Reimbursement and payment status for G0235

There is no Medicare payment rate for G0235. Its pricing indicator is 00, which means Part B does not price the service separately. Its coverage code is M, non-covered by Medicare. So searching the Physician Fee Schedule lookup tool for G0235 is a dead end. The code has no relative value units, so no facility or non-facility split and no geographic adjustment apply to it.

That matters commercially, because a practice quoting a Medicare rate for G0235 is quoting a number that does not exist. The table below shows where PET payment actually comes from.

Look up the CPT-level rates on the CMS hospital outpatient payment pages, which carry the current Addendum A and Addendum B files. For a G0235 study, the number the patient needs is your own self-pay charge, agreed and written on the ABN before the scan.

Related PET scan HCPCS and CPT codes

G0235 does not exist in isolation, and the codes around it are frequently described wrongly. The descriptors below come from the current CMS HCPCS file and the CPT nuclear medicine section, not from secondary lookup sites.

When to use G0235 vs. other PET codes

The decision runs in one direction, and it does not start with the G-codes. Identify the CPT code that describes the study, then check whether the indication is covered nationally or by your MAC. Only when both checks come back negative does G0235 become the right code.

The melanoma staging G-codes that older references cite, G0216 through G0218, no longer appear in the HCPCS file. Melanoma PET is billed with 78811 through 78816 under NCD 220.6.17. Add PI or PS to show whether the scan informs the initial or a subsequent treatment strategy.

For commercial payers, confirm which code set the plan recognizes before you submit. Practices using EMR software with integrated records can hold payer-specific coding notes against the patient file. The rule is then visible at the point of billing.

Common billing errors and how to avoid them

G0235 claims fail in a small number of predictable ways, and most of them come from treating it as a payable code. These are the errors worth designing out of your workflow.

• Quoting a Medicare rate for G0235. The code has no relative value units and no published allowable. A patient quoted a fee-schedule figure has been quoted a number that does not exist.
• Using G0235 when a CPT PET code describes the study. This is the most common error by volume. It converts a claim that would have paid under NCD 220.6.17 into a guaranteed denial.
• Filing GZ instead of GA. GZ tells Medicare no notice was given, so the practice writes the charge off. The fix is a signed ABN at scheduling, not a modifier change at submission.
• Treating G0219 or G0252 as covered fallbacks. Both are non-covered codes in their own right, and G0252 describes breast cancer imaging rather than cardiac work.
• Omitting the tracer line. The radiopharmaceutical is billed separately, and a PET claim without it looks incomplete to the payer’s edits.
• Citing NCD 220.6 in an appeal. The umbrella determination has been retired since January 1, 2022. Cite the surviving sub-determination or your MAC’s local article instead.

How Pabau supports PET documentation and coding accuracy

The documentation a G0235 study needs is rarely missing. It is usually scattered. The referral sits in an inbox and the indication sits in a clinical note. The signed ABN sits in a scanned folder, and the coder works from none of them. Pabau, an all-in-one practice management system, keeps those pieces on one patient record.

Digital forms and consent capture the ABN as a signed record against the patient file, dated at the moment the patient signed it. Treatment notes hold the indication and the clinical reasoning in the same place. Pabau Scribe, our AI scribe, can draft that note from the consultation itself. Before-and-after imaging and prior reports attach to the same file.

For imaging-heavy practices, the reporting layer matters too. You can see which documented indications are recurring, which referrals arrive without a stated indication, and which patients were never issued a notice. That turns a records request from a scramble into a lookup.

Keep imaging documentation on one patient record

Pabau brings clinical notes, signed patient forms, and imaging records together in one system. The trail behind a PET study is then complete before anyone asks for it. See how it fits your practice.

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Conclusion

The useful thing to know about HCPCS Code G0235 is that it is not a payment code. Coverage status M and pricing indicator 00 mean the claim is expected to deny. The work that decides the outcome happens before the patient is scanned. Get the CPT code right, check the surviving sub-determinations and your MAC’s article, and issue the ABN at scheduling.

Get that sequence wrong and the cost lands on the practice rather than the payer. A missed ABN turns a recoverable charge into a write-off. A G0235 line on a covered indication throws away a claim that would have paid. Neither error is a coding problem. Both are workflow problems.

The practices that handle this well keep everything in one place. The order, the indication, and the signed notice live in the same record as the appointment. Book a demo to see how Pabau keeps imaging documentation complete and easy to retrieve.

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