Your GI team ran an esophageal study, the report is signed, and the claim goes out under 91040. Three weeks later, it comes back denied. The test was fine. The code was wrong, or the paperwork behind it didn’t match what 91040 actually covers.
Such confusion is common since “esophageal manometry” and “esophageal balloon distension” sound similar and are grouped in the mind. It has several different services, each with its code. This guide will explain how CPT 91040 reimbursement works, what Medicare will pay, what documentation will pass review, and where claims fail. A2Z Billings has billers with over 150 years of combined experience working claims such as this one, and the repair work below is based on that experience.
What CPT 91040 actually describes
The AMA descriptor reads: “esophageal balloon distension study, diagnostic, with provocation when performed.” Here is what that looks like in the room. A thin catheter with an uninflated balloon is inserted through the patient's nose and into the mid-esophagus by the clinician. The balloon is inflated with air or water in small increments (usually 2 cc at a time) to a maximum of 30 cc. At each step, the clinician asks the patient about pain or pressure. The volume is measured when symptoms develop. The team may repeat the inflation or simulate it without adding anything to ensure that the patient is responding to the stretch rather than the setup. The balloon then emerges.
The study answers one question: is this patient’s recurring chest pain or trouble swallowing coming from the esophagus, or from somewhere else, like the heart? Payers will cover that question because the answer changes treatment.
One phrase deserves attention: “when performed.” Provocation sits inside the code. You don’t report it separately, and the code doesn’t demand it on every patient. Functional lumen imaging probes, sold under the EndoFLIP name, are billed by practices using code 91040 for tests; they only need to provide the answers.
91040 vs 91010: the mix-up that costs practices money
Esophageal manometry is a test that measures the contractile activity of the esophageal muscles and the relaxation of the lower sphincter. Esophageal motility (manometric) study, interpretation, and report. Reported with 91010. If the team adds a stimulant or an acid or alkali perfusion during the study, add-on code 91013 goes with 91010. The same code is used for high-resolution manometry. There is no separate HRM code. Device-maker coding guidance calls it 91010.
CPT 91040 measures something else. It tests how sensitive the esophagus is when stretched. No pressure waves, no sphincter tracings. A balloon, a volume, and the patient’s answers are all that is needed.
So the rule is simple: manometry gets 91010, and balloon distension gets 91040. A manometry test billed under 91040 describes a procedure the chart doesn’t support. The reviewer opens the report, sees pressure tracings and no balloon volumes, and the denial writes itself. The reverse error fails just as fast.
One doctor may order both studies for one patient. If so, each code should be documented separately. The report should show where one test ends and the next test begins.
When the study is medically necessary
Payers pay for 91040 when the chart explains why a balloon study was the right test. The usual story is recurrent chest pain with no clear cause or swallowing trouble that earlier testing didn’t explain. Reviewers tend to look for proof that the heart was checked first, because the study’s job is to separate esophageal pain from cardiac pain. If the cardiac workup lives in another practice’s system, pull it into the record.
Usually these codes are found on the diagnosis side: R07.89 (other chest pain), R13.10 (dysphagia, unspecified), K22.4 (dyskinesia of oesophagus), K22.0 (achalasia of the cardia), K21.9 (GERD without oesophagitis) when reflux is part of the picture. Use the most specific code the physician has indicated. The most common denial to get and to prevent is a diagnosis that does not match the clinical notes.
For this code each payer has its own list of covered diagnoses. Check the medical policy before you schedule the patient, not after the denial comes back.
What Medicare pays for CPT 91040
On the Medicare fee schedule for physicians, 91040 carries 17.27 total RVUs. Only 0.95 of that is physician work. Practice expense accounts for 16.24, and malpractice adds 0.08. At the current conversion factor, the national payment lands near $577 before geographic adjustment.
And read those numbers over again. Practice expense, including clinical staff time, supplies, and equipment, is 16.24. Malpractice adds 0.08. Right now the conversion factor is around $577 before geography is factored in to determine the national payment. Payment, the balloon, the pressure or imaging system, and the test performer are all included. If you have the equipment and the staff to do the study in your office, bill it as a full service. If you only bill the interpretation, that value goes to someone else.
Before you split a claim into professional and technical pieces, confirm on the fee schedule that the code supports the split. A modifier the schedule doesn’t allow gets the claim rejected.
Your actual check will differ from the national figure. Geographic adjustment moves it up or down, and commercial payers pay by contract, often as a percentage of the Medicare rate. Pull your contracted rate for 91040 from each major payer and compare it with that $577 benchmark. A rate far below it deserves a conversation at the next renewal.
Documentation that survives a review
The signed report is the claim. If the report is thin, the reviewer treats the claim as such.
A paid 91040 chart usually shows the reason for the study, including symptoms and the workup that came before it. It describes the setup: catheter placement, balloon type, and the medium used. It lists the inflation steps with volumes, the patient’s response at each one, and the volume at which symptoms were reproduced. If a simulated inflation was done, it says so and records the response.
Then comes the physician’s interpretation, signed and dated. Missing signatures cause more trouble than you’d expect. A report that sits unsigned for weeks can’t support a claim, and a late signature doesn’t always fix it.
State plainly whether provocation was performed. The descriptor allows either, but a chart that leaves the question open invites a letter asking about it.
Modifiers and bundling with endoscopy
Many patients get an upper endoscopy in the same session, and that’s where claims collide. EGD codes run from 43235 through 43259. The National Correct Coding Initiative publishes procedure-to-procedure edits that can bundle one code into another, and the files update every quarter. Look up your exact code pairs in the current table before you submit.
Each pair carries a modifier indicator. A 1 means a modifier can override the edit when the two services were truly separate. 0 means that no modifier will help, and the 2nd code is unpaid.
Modifier 59 is a separate procedure that is under a lot of scrutiny. Medicare also recognises the more limited X modifiers: XE – Separate Encounter; XS – Separate Structure; XP – Separate Practitioner; and XU – Unusual Non-Overlapping Service. Select the most specific one that fits. A different diagnosis alone doesn't justify 59. The chart must show that the balloon study was a medically necessary service with its indication, rather than an extension of the endoscopy.
Private payers run NCCI plus edits of their own, so a pair that clears Medicare can still stop at a commercial payer. Test both.
Place of service and ASC billing
CMS added 91040 to the ASC-covered procedures list in its latest outpatient and ASC final rule, a change tied to the American Society for Gastrointestinal Endoscopy and EndoFLIP studies. For practices with an ASC, that opens a billing path that wasn’t there before. The facility bills its fee under the ASC payment system, and the physician bills the professional service.
Hospital outpatient departments bill the facility side under the outpatient payment system, with the physician claim running separately.
Before you shift volume to an ASC, confirm that your MAC and each commercial payer accept the code in that setting. A Medicare list doesn’t bind a commercial contract.
Denial reasons and how to fix them
Four causes account for most of the 91040 denials, and they are worth worrying about.
The first is the wrong code. A manometry study goes out as 91040, or the reverse. Fix it by coding from the signed report, never from the order.
The second is a diagnosis mismatch. The ICD-10 code on the claim doesn’t match the symptoms in the note, or it isn’t on the payer’s covered list. Fix it by checking the policy at scheduling and coding to the highest specificity that the physician documented.
The third is a missing or unsigned interpretation. Fix it with a rule: no signed report, no claim.
The fourth is bundling with an endoscopy code and no valid modifier. Fix it with an NCCI pair check before submission, and attach the 59 or X modifier only when the indicator and chart both allow it.
When a denial does land, appeal fast. Attach the signed report, the physician’s reasoning for ordering the study, and the payer’s own policy language. Check the appeal window on the denial letter, because it’s short and it doesn’t bend.
Frequently asked questions
Is CPT 91040 for esophageal manometry?
No. 91010 Esophageal manometry (report with add-on 91013 when using a stimulant or perfusion). CPT 91040 is a test for esophageal balloon dilation.
What is the Medicare reimbursement for CPT 91040?
The code has 17.27 total RVUs on the Medicare fee schedule for physicians, or about $577 nationally before geographic adjustment. That number will depend on where you are and the commercial deals you have in place.
Can 91040 be billed with an EGD on the same day?
Occasionally. Check the NCCI edit for your exact code pair. If the modifier indicator is 1 and the chart shows a separate, necessary service, then modifier 59 or an X modifier can apply. If the indicator is 0, no modifier will release payment.
Does a payer require provocation to pay for 91040?
The descriptor reads “with provocation when performed", so the code applies regardless of whether provocation was used. Document which one happened.
What ICD-10 codes correspond with CPT 91040?
Common selections include R07.89, R13.10, K22.4, K22.0, and K21.9. Examine the code alongside the physician's documentation and assess the list of covered diagnoses for each payer.
Can an ambulatory surgery centre bill CPT code 91040?
CMS added the code to the ASC covered procedures list. Confirm that your MAC and your commercial payers accept it in the ASC setting before moving cases.
Get 91040 claims paid on the first submission.
Every denied esophageal study costs you twice, once in the unpaid claim and again in the staff hours spent chasing it. The practices that stop the bleeding: coding from the signed report, checking diagnoses before scheduling, and running the bundling check before every submission are the ones that make the whole system work. That’s the whole system.
A2Z Billings builds that system into your claims workflow, so GI codes like 91040 and 91010 go out right the first time. Pull your last ten esophageal claims today and compare each code to its report. If even one doesn’t match, contact A2Z Billings, and we’ll find the leak.