Understanding CPT Code for Gastric Emptying Study - A Complete Guide
A CPT code for gastric emptying study identifies a nuclear medicine test that measures how food moves from the stomach to the intestines. It is often ordered for patients with nausea, bloating, vomiting, or suspected gastroparesis. Because claims are closely reviewed, coding must match the study performed. This guide explains the codes, modifiers, documentation, ICD-10 links, HCPCS pairings, and current reimbursement rules.
Table of Contents
How a Gastric Emptying Study Really Works
A cpt code for gastric emptying study identifies a nuclear medicine test that measures how fast food moves from the stomach to the intestines. Patients usually eat a small meal mixed with a safe radioactive tracer, and images are taken at intervals. The test helps evaluate symptoms like nausea, bloating, or suspected gastroparesis. For more details, see this overview of gastric emptying study.
Cpt Code for Gastric Emptying Study — 78264 vs 78265 vs 78266
Gastric emptying studies are billed under three CPT codes, chosen based on the duration of the test and the regions imaged. Using the correct code ensures claims match the documented procedure and reduces denial risk.
CPT Code 78264 – Standard Gastric Emptying
This code is reported when only the stomach is imaged, usually over a 4-hour period. According to the Society of Nuclear Medicine and Molecular Imaging (SNMMI), the 4-hour solid meal protocol detects delayed gastric emptying in nearly 30–40% of patients with suspected gastroparesis. Because most referrals involve evaluation of upper GI symptoms like nausea or bloating, 78264 is by far the most frequently billed CPT code for gastric emptying studies in the U.S.
CPT Code 78265 – Stomach and Small Bowel Transit
This code applies when imaging extends beyond the stomach into the small bowel. Studies show that about 15–20% of patients with gastric motility complaints also exhibit small bowel transit abnormalities, which makes this code important when gastroparesis alone does not explain the patient’s symptoms. The procedure typically lasts 24–26 hours and helps physicians evaluate both gastric and intestinal motility in one extended protocol.
CPT Code 78266 – Full Gastrointestinal Transit
This code is reserved for comprehensive studies of stomach, small bowel, and colon motility. It is the least common CPT code, used in fewer than 5% of gastric emptying claims nationwide, since multi-day GI transit studies are generally ordered only in complex or refractory cases. The test can last 2–3 days and provides a complete picture of gastrointestinal transit time, which is especially valuable for patients with generalized motility disorders.
When to Choose the Correct Gastric Emptying Procedure Code
Selecting the right CPT code for a gastric emptying study depends on three main factors: which regions of the gastrointestinal tract are imaged, how long the study lasts, and which meal protocol is used. Each code corresponds to a specific scenario, and payers will only reimburse if the documented details align with the billed code. Below are the main considerations that determine how the study should be documented and reported.
Choosing Based on Scope of Imaging
Use CPT 78264 if the study measures gastric emptying of a solid, liquid, or dual-phase meal limited to the stomach only and images are taken at intervals up to 4 hours.
Use CPT 78265 if the study tracks food from the stomach into the small bowel, extending beyond 4 hours and lasting up to 24–26 hours.
Use CPT 78266 if the protocol includes the entire gastrointestinal tract, covering stomach, small bowel, and colon, usually over 2–3 days.
Choosing Based on Study Duration
For short tests (≤ 4 hours) that stop at the stomach, select 78264.
For extended tests (24 hours) where imaging continues into the small bowel, select 78265.
For multi-day studies (48–72 hours) that follow food into the colon, select 78266.
Meal Protocol Considerations
If a solid meal protocol is used and imaging ends at 4 hours → bill 78264.
If a liquid or dual-phase meal is documented and transit into the small bowel is measured → bill 78265.
If the meal and tracer are followed through to the colon over several days → bill 78266.
“When your CPT doesn’t match your scan, your claim doesn’t match your check.”
Modifiers in Nuclear Medicine Gastric Scan Billing
Correct modifier use is essential when billing gastric emptying study CPT codes. Each modifier identifies exactly which part of the service was provided:
Modifier 26 – Professional Component
Use this when billing only for the physician’s interpretation and report. Example: a radiologist interprets the gastric emptying study performed at a hospital that owns the imaging equipment.Modifier TC – Technical Component
Report this modifier when billing only for the technical portion, which covers the scanner, technologist time, and radiopharmaceuticals. Example: the hospital bills TC while the radiologist bills 26.Modifier 59 – Distinct Procedural Service
Apply this when the gastric emptying study is performed independently of another nuclear medicine test on the same date. Example: if a patient undergoes both a gastric emptying study and a hepatobiliary scan, use modifier 59 to show they are separate procedures.Modifier 52 – Reduced Services
Use 52 if the study is partially completed (e.g., patient only tolerated 2 hours instead of 4).Modifier 53 – Discontinued Services
Use 53 if the procedure had to be stopped after it began (e.g., patient could not continue after ingesting the meal).
“Modifiers are like labels on packages — if you put the wrong one, the delivery (your reimbursement) gets returned.”
Documentation Requirements for Gastric Emptying Test Coding
When billing a gastric emptying study under CPT codes 78264, 78265, or 78266, payers require complete documentation that matches the procedure performed. Missing or incomplete details are one of the most common reasons for claim denials and audit flags in nuclear medicine. Every report must include both the technical aspects of the test (meal, tracer, timing, regions imaged) and the clinical interpretation by the physician. Below is the list of documentation elements that must be recorded in the medical report to support coding, compliance, and reimbursement.
Patient demographics: name, DOB, MRN
Clinical reason or indication for study
Referring physician’s name and details
Radiotracer name, form, and dosage used
Standardized meal type and description
Imaging start and end times recorded
Imaging intervals at set time points
Regions imaged: stomach, bowel, colon
% gastric retention values documented
Physician interpretation and signature
ICD-10 Links Commonly Paired with Gastric Emptying Studies
Correct ICD-10 coding is essential when reporting gastric emptying studies because it establishes medical necessity for the procedure. Payers require the diagnosis code to match the patient’s documented symptoms or condition that justified the test. Commonly used ICD-10 codes reflect disorders such as gastroparesis, nausea, vomiting, or abdominal bloating. Choosing the right diagnosis code not only supports reimbursement but also reduces the likelihood of claim denials or post-payment audits.
Common ICD-10 Codes for Gastric Emptying Studies
Using precise ICD-10 codes helps justify medical necessity and avoids payer rejections.
Radiopharmaceutical/HCPCS with the Cpt Code for Gastric Emptying Study
In addition to the CPT code for the gastric emptying study itself, billing often requires a separate HCPCS code to capture the radiopharmaceutical used. Payers expect both codes to appear on the claim to fully represent the service provided. Missing or incorrect HCPCS coding can lead to undercoding and lost reimbursement.
· A9560 – Tc-99m sulfur colloid (diagnostic): The most common tracer for solid meal gastric emptying studies.
· A4641 – Radiopharmaceutical supply: Used when the tracer is supplied separately.
Correctly pairing the CPT and HCPCS codes ensures that the procedure, tracer, and supplies are all billed, supporting both compliance and full payment. The American Gastroenterological Association’s coding resources provide additional details on reporting nuclear medicine supplies.
Reimbursement and Payer Policy Notes for Gastric Motility Testing Codes
Payment policies for gastric emptying studies vary across Medicare and commercial insurers. Reimbursement depends not only on the procedure performed but also on how well the claim aligns with documentation and payer-specific requirements. Understanding these rules helps providers avoid denials, comply with audits, and secure proper payment.
Medicare and National Guidelines
Medicare requires documentation of meal type, tracer, imaging times, and interpretation. In 2025, CMS ruled that radiopharmaceuticals costing over $630/day will be reimbursed separately, not bundled with the test. This change improves access but increases audit checks. MACs now review gastric emptying claims more aggressively, so even minor missing details can cause denials.
Commercial Payer Rules
Most commercial payers require prior authorization before gastric emptying studies. Many restrict coverage to ICD-10 codes like K31.84 (Gastroparesis). Some insurers now follow CMS trends by unbundling high-cost tracers, but rules vary. Practices should always confirm payer-specific guidelines to avoid denied or delayed claims.
Audit and Compliance Risks
Gastric emptying studies remain frequent audit targets. With the radiopharmaceutical market projected at $13.21B in 2025, oversight is increasing. Missing imaging intervals, mismatched CPT/HCPCS codes, or incomplete tracer details are the most common red flags. Proper documentation is the only way to defend against denials.
For real-world results, see this case study on gastroenterology revenue recovery.
A CPT code for gastric emptying study identifies a nuclear medicine test that measures how food moves from the stomach to the intestines. It is often ordered for patients with nausea, bloating, vomiting, or suspected gastroparesis. Because claims are closely reviewed, coding must match the study performed. This guide explains the codes, modifiers, documentation, ICD-10 links, HCPCS pairings, and current reimbursement rules.
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