CPT code 78264: Gastric emptying study billing guide

CPT code 78264 is the nuclear medicine code for a gastric emptying imaging study of the stomach alone. The study can use a solid meal, a liquid meal, or both phases.

The moment the imaging follows the meal past the stomach, the correct code becomes 78265 or 78266. That boundary matters to billers and practice managers, because scope errors and thin medical necessity notes cause most denials on this code.

Below you will find the official descriptor, the ICD-10 pairings, the modifiers, and how Medicare pays. The route a claim takes and the checks that keep it clean follow.

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Key takeaways

CPT code 78264 covers a gastric emptying imaging study of the stomach only, with no small bowel or colon transit imaging.

The usual ICD-10 pairings are K31.84 for gastroparesis, K30 for functional dyspepsia, and R11.2 for nausea with vomiting.

Modifier 26 bills the interpretation and modifier TC bills the technical side, so split arrangements carry one of them on every claim.

Most denials trace back to an unsigned order, a thin medical necessity note, or a code that does not match the imaging scope.

Practice management software like Pabau submits claims electronically and filters outcomes by date, insurer, or invoice ID.

What CPT code 78264 covers, and where it stops

CPT code 78264 sits in the Nuclear Medicine section of the AMA’s CPT code set. Its official descriptor reads: Gastric emptying imaging study (eg, solid, liquid, or both).

The code applies only while the protocol stays in the stomach. Once imaging tracks transit beyond it, 78265 or 78266 takes over.

The study itself is straightforward. The patient eats a standardized meal labeled with a radiopharmaceutical, usually technetium Tc 99m sulfur colloid.

Images follow at timed intervals, and the percentage of the meal still in the stomach is calculated at each one. A nuclear medicine physician then reads the images and signs a formal report.

That 000 global period is useful to know at the scheduling desk. No follow-up period is bundled into the code, so each imaging session stands on its own claim. Schedulers never have to work around a surgical-style global window.

When physicians order a gastric emptying study

Physicians order this study when symptoms point to a stomach that empties too slowly. Gastroparesis is the leading indication, and diabetes is the most frequent cause behind it. Scintigraphy remains the standard way to quantify delayed emptying, which is why the study keeps its place in the workup. These are the indications payers expect to see in the note.

• Gastroparesis (K31.84): delayed gastric emptying, confirmed or clinically suspected, particularly in diabetic patients
• Functional dyspepsia (K30): upper GI symptoms without a structural cause, where motility findings guide management
• Nausea with vomiting, unspecified (R11.2): persistent symptoms once other causes have been excluded
• Post-surgical gastric assessment: motility checks after gastric bypass, fundoplication, or vagotomy
• Diabetic autonomic neuropathy: motility evaluation in patients with established autonomic nerve damage
• GERD workup: where delayed emptying is suspected of contributing to reflux symptoms

The indication has to be on the record before imaging is ordered, not reconstructed afterwards. Payers deny CPT 78264 when the physician’s note carries no symptom history and no reason to choose nuclear imaging over other tests.

78264, 78265, or 78266: The scope of imaging decides

The three gastric emptying codes differ on one axis only, which is how far the imaging follows the meal. CPT 78264 covers the stomach. CPT 78265 adds small bowel transit. CPT 78266 adds colon transit on top of both.

Picking the wrong one is among the most common billing errors in nuclear medicine gastroenterology.

Bill 78264 only where the protocol is limited to gastric clearance. If the order or the report documents small bowel or colon transit, move up to 78265 or 78266.

Coding down to 78264 after a wider study understates the work the report describes, and it is a compliance problem in its own right.

Pair 78264 with the ICD-10 code your chart supports

Medical necessity lives in the diagnosis code, so the pairing decides whether the claim survives review. The codes below reflect accepted pairings under CMS ICD-10 coding guidance and the applicable Local Coverage Determinations.

Those LCDs vary by Medicare Administrative Contractor, so check your MAC’s current policy before you submit.

K31.84 is the most specific code for gastroparesis, so it belongs first on most 78264 claims. Reaching for a symptom code such as R11.2 while the chart already documents gastroparesis weakens the claim.

The payer sees a thinner rationale than the record supports, and a medical necessity review often follows.

Modifiers 26 and TC split the claim in two

Modifier choice on CPT 78264 follows the billing arrangement between the reading physician and the imaging facility. Three modifiers cover almost every arrangement you will meet.

Laterality modifiers are a different story. LT and RT do not apply to gastric imaging, because the stomach is not a paired structure. Appending either one can trip a claim edit or a rejection, so check your MAC’s policy before you use them on this code.

How Medicare pays for a 78264 gastric emptying study

Medicare pays CPT 78264 through the Physician Fee Schedule, and the amount depends on where you practice and how you bill. The rate is built from work, practice expense, and malpractice RVUs. Those are adjusted for your locality, then multiplied by the annual conversion factor.

Look up the current figure for your region with the CMS Physician Fee Schedule lookup tool. Locality adjustments move the number enough that a national average makes a poor stand-in.

Setting changes the arithmetic on the technical side. Hospital outpatient departments bill under the Outpatient Prospective Payment System, so their rates differ from a free-standing imaging center.

The reading physician still bills the professional component under the fee schedule either way. When the remittance arrives, check which component was paid before anyone books the balance as underpayment.

Documentation that keeps a 78264 claim out of review

Documentation decides more 78264 claims than any other factor, and incomplete records drive a large share of first-pass denials. The physician’s order and the nuclear medicine report have to cover all seven elements below between them.

• Written physician order: signed and dated by the referring or treating physician, naming the study and the clinical indication
• Clinical indication in the record: symptom history, duration, prior treatment, and the reason for nuclear imaging over other tests
• Imaging protocol used: solid phase, liquid phase, or both, plus the imaging intervals and patient positioning
• Radiopharmaceutical details: agent, dose administered, route, and the time it was given
• Formal interpretation report: signed by the interpreting physician, with gastric retention percentages at each interval and a conclusion
• Medical necessity attestation: a note that the clinical picture supported the study, rather than routine screening
• ICD-10-CM diagnosis code: matched to the indication recorded in both the order and the physician’s note

Retention percentages deserve particular attention. A narrative impression reads well clinically, but it gives a reviewer no figure to measure the study against. Quantified intervals are what turn a records request into a closed file.

Prior authorization depends on the payer, not the code

Traditional Medicare does not require prior authorization for most nuclear medicine diagnostic studies, and that includes gastric emptying imaging.

Medicare Advantage plans and commercial insurers often do. Because the requirement travels with the plan rather than the code, confirm it before the patient is scheduled.

• Traditional Medicare: no prior authorization in most cases; medical necessity is judged after the claim, against LCD criteria
• Medicare Advantage plans: often required, with criteria that mirror the LCD and sometimes add documentation thresholds
• Commercial insurers: varies widely; many want evidence of dietary changes or prokinetic therapy first
• Medicaid: set by the state, so check your state’s policy for nuclear medicine gastroenterology

A strong authorization request attaches the referring physician’s order, a summary of the indication, prior treatment history, and any relevant test results.

Verifying benefits at scheduling is what surfaces the requirement in time. It also tells the front desk what the patient will owe before they arrive for imaging.

How a 78264 claim moves from order to payment

A gastric emptying claim passes through six stages, and each one leaves behind a document the payer may ask for later. Walking the route in order shows where the administrative work sits.

It starts with the referring physician’s signed order, which names the study and the indication. Scheduling then verifies the plan and requests authorization where one is needed. The study follows, imaged at timed intervals with the meal the protocol specifies.

From there the work turns administrative. The nuclear medicine physician signs a report carrying retention percentages at each interval.

Coding builds the claim from that report, pairing 78264 with the supporting ICD-10 code and adding modifier 26 or TC where billing is split. The payer adjudicates, and the remittance either posts a payment or returns a denial code to work.

Run these checks before you submit the claim

Most 78264 denials are preventable at the desk, and the check takes a couple of minutes. Run this list before the batch goes out, and a clean claim becomes the default rather than the exception.

• The order is signed, dated, and names a gastric emptying study
• The report documents the stomach only, with no small bowel or colon transit
• Retention percentages appear for every imaging interval
• The diagnosis code on the claim also appears in the physician’s note
• Modifier 26 or TC is present where the components are billed separately
• No LT or RT modifier is attached to the line
• The authorization number is on the claim for any plan that required one

Seven mistakes that get a 78264 claim denied

Gastric emptying claims deny more often than many comparable nuclear medicine codes, mainly because the documentation rules are specific and payer policies differ.

Each of the mistakes below has its own fix, so name the cause before anyone resubmits.

• Missing or incomplete physician order: the usual denial trigger; the order must be signed, dated, and specific about the indication
• Thin medical necessity documentation: a vague symptom line without prior workup fails LCD criteria, so the note has to say why scintigraphy was indicated
• Wrong code for the scope of study: billing 78264 when the report documents small bowel transit creates a mismatch; move to 78265 or 78266
• Incorrect or missing modifier: no modifier on split billing, or LT and RT where they do not belong, produces an edit
• Diagnosis code mismatch: a code outside your MAC’s LCD for nuclear medicine gastroenterology returns a medical necessity denial
• Missing prior authorization number: on plans that require it, the first submission denies automatically
• Unbundling with related codes: other nuclear medicine or GI codes on the same date, without modifier 59 and support for it, trigger NCCI edits

When a claim comes back, read the remittance before you touch it. The denial codes separate a medical necessity problem from a missing record, and the two need different work.

Medical necessity usually calls for a peer-to-peer review or a physician attestation letter. A documentation failure calls for a corrected claim with the records attached.

Where audits find problems with CPT 78264

Audit exposure on this code comes from two directions: NCCI bundling edits, and medical necessity documentation that does not hold up.

The Office of Inspector General and the MACs review nuclear medicine gastroenterology codes periodically. Studies billed alongside GI endoscopy on the same service date draw the most attention.

NCCI bundling edits

The National Correct Coding Initiative publishes procedure-to-procedure pairs that cannot be billed together without a modifier.

Check the current table before billing CPT 78264 on the same date as another gastroenterology or nuclear medicine code. Modifier 59 is the standard bypass, but it only holds where the documentation shows two genuinely separate services.

Medical necessity audit flags

Volume attracts attention. A practice billing 78264 heavily for its size or specialty mix can draw a Recovery Audit Contractor or MAC review. Three patterns come up repeatedly:

• studies ordered with no record of prior conservative treatment
• repeat studies in a short interval, with no documented change in status
• a claim diagnosis that never appears in the contemporaneous note

Regular internal audits of 78264 claims against the documentation remain the best defense. A practice management system makes the sampling step quicker. In Pabau, claim outcomes filter by date, insurer, or invoice ID while you pull the quarter’s list.

How Pabau keeps 78264 documentation and claims in one record

The pieces of a gastric emptying claim often live apart. The order sits in the EHR, the report arrives from the imaging side, and the charge is typed into billing from a printout. Two weeks later a denial lands in a payer portal that nobody has open. Whoever works it has to rebuild the story from three systems.

Practice management software like Pabau keeps that chain on one patient record. The clinical note, the coded charge, and the claim stay together, so the documentation a payer asks for is attached to the claim it supports.

Claims go out electronically through Claim.MD, a clearinghouse connected to thousands of US payers, and remittances post back against the invoice they came from.

For a billing team, the practical benefit is fewer places to look. Pabau’s claims software for billers lists submitted claims and filters them by date, insurer, or invoice ID.

That is enough to pull a quarter of nuclear medicine claims for an internal check. Templated clinical notes can prompt the order details, the protocol, and the retention percentages while the study is fresh.

Keep nuclear medicine notes and claims together

Pabau links clinical documentation to the claim it supports, so gastroenterology and nuclear medicine practices can submit, track, and work denials from one patient record.

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Conclusion

Getting CPT 78264 paid comes down to three habits. Match the code to the scope of imaging the report describes. Lead with the most specific diagnosis the chart supports. Capture the order, the protocol, and the retention percentages while the study is fresh, rather than at appeal.

The trade-off worth remembering is where the effort sits. A few minutes of checking before submission replaces a much longer appeal later. Practices with a low denial rate on this code simply front-load that work. If the documentation is already in the claim, an audit becomes a filing exercise instead of a reconstruction.

If the pieces of your nuclear medicine claims are scattered across systems today, that is the problem worth fixing first. Book a demo to see how Pabau keeps the note, the charge, and the claim on one record. You can then filter outcomes by date, insurer, or invoice ID.

Continue your research

Need to understand how clean claims are built? Clean claim submission walks through every element that must be present before a claim reaches the payer.

Want to spend less time chasing denials? Denial management in healthcare covers root-cause analysis and appeal workflows for common denial patterns.

Exploring how clearinghouse billing works end to end? Claim.MD clearinghouse overview explains how electronic claim routing, eligibility, and ERA remittance fit together.

New to the billing cycle behind a code like this? What is medical billing sets out how a service becomes a claim and then a payment.

Building an internal audit routine? Medical billing compliance explains the controls that keep coding and documentation defensible.

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