CPT code 31235: Sinus endoscopy, diagnostic sphenoid sinusoscopy2026 Medicare rate & RVUs in California
ENT clinicians report diagnostic sphenoid sinus endoscopy to inspect the sphenoid sinus through the nose when evaluating suspected or known sinus disease.
Medicare pays $326.38–$407.75 for 31235 in the office in California, from Chico, CA to San Benito County, CA. Which amount applies depends on the service address.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
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On this page 9 sections
What 31235 covers
An otolaryngologist passes an endoscope through the nasal passage to examine the sphenoid sinus. The diagnostic view can help assess suspected sphenoid sinus inflammation, a lesion, or other findings identified during evaluation of sinus symptoms or imaging. The service is performed in settings such as an ENT office or operating room when the purpose is diagnostic visualization rather than sphenoid sinus surgery.
Report the code when documentation supports examination of the sphenoid sinus, not merely a general nasal examination or visualization of another sinus. If the same session includes related nasal or sinus endoscopies, CMS endoscopy-family pricing applies. The code has a 0-day global period, so same-day preoperative and postoperative care is included. Modifier 50 identifies bilateral performance and CMS pays it at 150%. Assistant-at-surgery payment requires documentation of medical necessity; co-surgeons and team surgery are not permitted.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
Where 31235 pays more and less in California
The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.
29 payment localities
$326.38 to $407.75
29 of 29 payment localities
| Payment locality | Office | Facility |
|---|---|---|
| Bakersfield, CA | $327.45 | $138.56 |
| Chico, CA | $326.38 | $137.49 |
| El Centro, CA | $326.44 | $137.55 |
| Fresno, CA | $326.38 | $137.49 |
| Hanford, CA | $326.38 | $137.49 |
| Los Angeles, CA | $348.47 | $144.59 |
| Madera, CA | $326.38 | $137.49 |
| Marin County, CA | $398.72 | $155.71 |
| Merced, CA | $326.38 | $137.49 |
| Modesto, CA | $326.38 | $137.49 |
| Napa, CA | $377.07 | $149.91 |
| Oxnard, CA | $346.64 | $142.92 |
| Redding, CA | $326.38 | $137.49 |
| Rest of California | $326.38 | $137.49 |
| Riverside, CA | $330.38 | $141.49 |
| Sacramento, CA | $342.22 | $141.78 |
| Salinas, CA | $340.94 | $141.19 |
| San Benito County, CA | $407.75 | $159.22 |
| San Diego, CA | $348.78 | $142.65 |
| San Francisco, CA | $398.30 | $155.29 |
| San Luis Obispo, CA | $335.50 | $139.20 |
| Santa Clara County, CA | $406.03 | $157.50 |
| Santa Cruz, CA | $351.96 | $142.56 |
| Santa Maria, CA | $342.17 | $141.21 |
| Santa Rosa, CA | $355.49 | $143.85 |
| Stockton, CA | $326.38 | $137.49 |
| Vallejo, CA | $376.46 | $149.31 |
| Visalia, CA | $326.38 | $137.49 |
| Yuba City, CA | $326.38 | $137.49 |
How the 31235 rate is calculated
Each of 31235’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 31235
RVUs × geographic indexes × conversion factor
Work2.57
2.57 RVUs× 1.000 GPCI
Practice expense6.35
6.35 RVUs× 1.000 GPCI
Malpractice0.37
0.37 RVUs× 1.000 GPCI
Adjusted RVUs
9.2900
Conversion factor
$33.4009
Medicare rate
$310.29
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 31235
The CMS indicators that decide how 31235 is paid alongside other services.
CMS payment indicators · 31235
Sinus endoscopy, diagnostic sphenoid sinusoscopy
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 000 | Same-day global: pre- and post-op care on the day of the procedure is included. |
| Multiple procedures | 3 | Endoscopy family rules apply. |
| Bilateral (modifier 50) | 1 | Bilateral with modifier 50 pays 150% of the fee schedule amount. |
| Assistant at surgery (80/81/82/AS) | 0 | Not paid without supporting documentation. |
| Co-surgeons (62) | 0 | Not permitted. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
What modifiers do to the payment
Modifier 50 · payment effect
With and without the modifier
31235 without 50 · national office
$310.29
Sinus endoscopy, diagnostic sphenoid sinusoscopy
31235-50 · Bilateral: 150%
$465.44
Both sides on one line with modifier 50 are paid at 150% of the fee schedule amount (subject to multiple-procedure rules with other procedures).
31235 compared with similar codes
Compare codes · National
5 codes, side by side
How to choose
- 31231Nasal endoscopyDiagnostic, without sinusoscopy
- 31231 describes diagnostic nasal endoscopy without sphenoid sinusoscopy. Report 31235 when the documented examination specifically reaches the sphenoid sinus.
- 31233Sinus endoscopyMaxillary sinus
- 31233 is diagnostic endoscopy of the maxillary sinus; 31235 is selected for diagnostic examination of the sphenoid sinus.
- 31287SphenoidotomyWithout tissue removal
- 31287 describes surgical sphenoidotomy, not diagnostic visualization alone. Choose it when the operative work includes sphenoid surgery.
- 31288Sphenoid surgerySphenoid tissue removal
- 31288 applies when sphenoid surgery includes tissue removal. Diagnostic sphenoid sinusoscopy without that surgical work is distinguished by 31235.
31235 billing questions
How does this differ from diagnostic nasal endoscopy, 31231?
31235 includes diagnostic examination of the sphenoid sinus. Use 31231 for a diagnostic nasal examination that does not include sphenoid sinusoscopy.
How does this differ from diagnostic maxillary sinus endoscopy, 31233?
The distinction is the sinus examined: 31235 documents sphenoid sinusoscopy, while 31233 addresses maxillary sinusoscopy.
Can diagnostic sphenoid endoscopy be separately reported with sphenoid surgery?
When the same session proceeds to sphenoid surgery, compare the documented operative service with the surgical code, such as 31287 or 31288. Do not assume the diagnostic examination is separately reportable.
What modifier identifies bilateral performance?
Use modifier 50 for bilateral performance; CMS pays this procedure at 150% when reported bilaterally.
What documentation supports reporting 31235?
Document that the endoscope was used to examine the sphenoid sinus and record the diagnostic findings. A note describing only general nasal inspection does not establish sphenoid sinusoscopy.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file lines behind this rate
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