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CPT code 31297: Sinus dilation, sphenoid ostium2026 Medicare rate & RVUs in King County, WA

Endoscopic balloon dilation of the sphenoid sinus opening to improve drainage, reported when the surgeon treats the sphenoid ostium by dilation rather than sinusotomy.

CMS RVU26DEffective Oct 1, 2026One payment locality1.3K Medicare services in 2024

In King County, WA, Medicare pays $1,900.64 for 31297 in the office and $132.64 when it’s performed in a hospital or facility.

$1,900.64Office (non-facility)
$132.64Hospital or facility
+21.5%vs the national office rate ($1,564.50)

Check a contract rate as a % of Medicare · 31297 nationwide

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

We’ll open 31297 for the payment locality that covers the ZIP.

On this page 11 sections
  1. Rate in King County, WA
  2. What 31297 covers
  3. Compared with other areas
  4. Rate map
  5. How it’s calculated
  6. Payment rules
  7. Related codes
  8. Rate history
  9. Where it applies
  10. Billing questions
  11. Sources

What 31297 covers

An otolaryngologist uses a nasal endoscope to reach and dilate the sphenoid sinus opening, commonly with a balloon catheter, to improve drainage through the natural ostium. The procedure may be performed in an office or operating room for a patient with sphenoid sinus disease or an obstructed sphenoid opening. Fluoroscopy, when used, is included in the service.

Report 31297 when the documented operative work is dilation of the sphenoid sinus ostium; distinguish it from a sphenoidotomy that opens the sinus by incision or removes tissue. The operative note should identify the treated sinus, side, endoscopic approach, and dilation performed. This is a 0-day global procedure, so same-day preoperative and postoperative care is included. Modifier 50 identifies bilateral treatment and CMS pays the bilateral procedure at 150%. When related endoscopies are performed together, endoscopy family pricing applies. An assistant is paid only when medical necessity is documented; 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.

How King County, WA compares for 31297

Across 109 of 109 payment localities, the office rate for 31297 runs from $1,350.98 in Arkansas to $2,218.72 in San Benito County, CA. King County, WA pays $1,900.64. The RVUs are the same everywhere; the geographic indexes change the dollars.

31297 in King County, WA vs other payment areas
  1. King County, WA · this page$1,900.64
  2. Rest of Washington · Washington$1,640.73−$259.91
  3. Los Angeles, CA · California$1,833.27−$67.37
  4. Washington, DC area · District of Columbia$1,832.34−$68.30
  5. Miami, FL · Florida$1,643.28−$257.36
  6. Chicago, IL · Illinois$1,587.99−$312.65
  7. Manhattan, NY · New York$1,815.25−$85.39

Other areas in Washington first, then benchmark localities. Bars start at $0.

Every other payment area

31297 in every other Medicare payment locality
Payment localityOfficeFacility
AlaskaAlaska$1,694.59$160.02
AlabamaAlabama$1,375.16$114.36
ArkansasArkansas$1,350.98$113.23
ArizonaArizona$1,517.10$120.86
Bakersfield, CACalifornia$1,702.71$123.47
Chico, CACalifornia$1,701.68$122.43
El Centro, CACalifornia$1,701.74$122.49
Fresno, CACalifornia$1,701.68$122.43

31297 rates by state

Office rate range in each state. Select a state to see its payment localities.

MEWIVTNHMTNDMNMINYMARIWAIDWYSDIAILINOHPANJCTORNVUTCONEMOKYWVVAMDDECAAZNMKSOKARTNNCSCDCTXLAMSALGAFLAKHI

Explore a state

Local rates. Clear comparisons.

Hover or focus a tile to see its rate range. Select it to open the state’s fee schedule.

$1,350.98

$1,960.20

Color shows the midpoint of each state’s locality range.

View every state and territory as a table
31297 office rate range by state
State / territoryOffice rate rangeLocalities
AK$1,694.591
AL$1,375.161
AR$1,350.981
AZ$1,517.101
CA$1,701.68–$2,218.7229
CO$1,657.091
CT$1,682.031
DC$1,832.341
DE$1,546.011
FL$1,505.74–$1,643.283
GA$1,407.73–$1,590.722
GU$1,761.231
HI$1,761.231
IA$1,432.041
ID$1,440.321
IL$1,443.12–$1,614.114
IN$1,450.791
KS$1,417.131
KY$1,399.981
LA$1,394.60–$1,479.232
MA$1,641.40–$1,852.192
MD$1,581.98–$1,832.343
ME$1,442.11–$1,546.802
MI$1,437.90–$1,521.192
MN$1,598.751
MO$1,360.91–$1,493.823
MS$1,356.621
MT$1,564.471
NC$1,461.471
ND$1,557.361
NE$1,443.601
NH$1,623.391
NJ$1,704.36–$1,806.002
NM$1,444.661
NV$1,563.961
NY$1,487.28–$1,858.285
OH$1,436.451
OK$1,404.211
OR$1,555.04–$1,726.192
PA$1,443.05–$1,628.642
PR$1,580.521
RI$1,613.321
SC$1,450.751
SD$1,556.511
TN$1,424.891
TX$1,431.08–$1,648.728
UT$1,474.891
VA$1,535.92–$1,832.342
VI$1,580.521
VT$1,543.831
WA$1,640.73–$1,900.642
WI$1,494.311
WV$1,376.721
WY$1,561.371

See 31297 in every payment locality

How the 31297 rate is calculated

Each of 31297’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 · 31297

RVUs × geographic indexes × conversion factor

Office or facility?

Work2.38

2.38 RVUs× 1.000 GPCI

Practice expense44.10

44.10 RVUs× 1.000 GPCI

Malpractice0.36

0.36 RVUs× 1.000 GPCI

Adjusted RVUs

46.8400

Conversion factor

$33.4009

Medicare rate

$1,564.50

Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.

The exact King County, WA inputs and CMS source lines

PPRRVU2026_Oct_nonQPP.csv

3,552

Code
31297
Physician work
2.38
Practice expense
44.10
Malpractice
0.36

GPCI2026.csv

108

Locality
King County, WA
Physician work
1.050
Practice expense
1.227
Malpractice
0.817
Office calculation for 31297 in King County, WA
ComponentRVULocality factorAdjusted
Physician work2.38× 1.0502.4990
Practice expense44.10× 1.22754.1107
Malpractice0.36× 0.8170.2941
Total RVUs56.9038
Conversion factor× 33.4009

Office rate, King County, WA$1900.64

Office: (2.38 × 1.05 + 44.1 × 1.227 + 0.36 × 0.817) × $33.4009 = $1900.64

Facility: (2.38 × 1.05 + 0.96 × 1.227 + 0.36 × 0.817) × $33.4009 = $132.64

Open 31297 in the RVU calculator

Payment rules and modifiers for 31297

The CMS indicators that decide how 31297 is paid alongside other services.

CMS payment indicators · 31297

Sinus dilation, sphenoid ostium

RuleCMS valueWhat it means
Global period000Same-day global: pre- and post-op care on the day of the procedure is included.
Multiple procedures3Endoscopy family rules apply.
Bilateral (modifier 50)1Bilateral with modifier 50 pays 150% of the fee schedule amount.
Assistant at surgery (80/81/82/AS)0Not paid without supporting documentation.
Co-surgeons (62)0Not permitted.
Team surgery (66)0Not permitted.
Professional/technical0Physician service: no professional/technical split.

What modifiers do to the payment

Modifier 50 · payment effect

With and without the modifier

31297 without 50 · national office

$1,564.50

Sinus dilation, sphenoid ostium

31297-50 · Bilateral: 150%

$2,346.75

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).

When to use modifier 50

Codes related to 31297

Related codes aren’t interchangeable: bill the code that matches the service performed.

Codes related to 31297
CodeHow it relatesOffice range, King County, WA
Same family
31298Sinus dilation, frontal and sphenoidCombines frontal and sphenoid ostial dilation; 31297 is for the sphenoid site.$3,604.43
31296Sinus dilation, frontal sinusDilation at the frontal sinus ostium rather than the sphenoid ostium.$1,943.44
31295Sinus dilation, maxillary sinus ostiumDilation at the maxillary sinus ostium rather than the sphenoid ostium.$1,914.73
Used instead
31287Sphenoidotomy, without tissue removalEndoscopic sphenoidotomy is a different approach from dilation of the sphenoid ostium.No office rate
31288Sphenoid surgery, sphenoid tissue removalSphenoidotomy with tissue removal, rather than ostial dilation.No office rate

How 31297 has changed in King County, WA

31297 · Office / nonfacility

$1900.64

Effective 2026-10-01

The base rate is $79.13 higher than on 2025-10-01, moving from $1821.51 to $1900.64 (4.3%).

It is unchanged from the immediately preceding available release, effective 2026-07-01.

Base rate by release · bars start at $0 · select a bar to compare

One bar per available release, ordered by effective date. Missing rates remain gaps. These comparisons hold the code, setting and locality identifiers constant; they do not isolate which policy or input caused a change.

What changed, release by release

  1. January 1, 2026

    RVU26A

    $1821.51changed to$1900.64

    • Conversion factor 32.3465 changed to 33.4009
    • Work RVU 2.44 changed to 2.38
    • Practice expense RVU 43.82 changed to 44.10
    • Work GPCI 1.043 changed to 1.050
    • Practice expense GPCI 1.220 changed to 1.227
    • Malpractice GPCI 0.853 changed to 0.817

    Held through RVU26B, RVU26C, RVU26D.

  2. January 1, 2025

    RVU25A

    $1965.47changed to$1821.51

    • Conversion factor 33.2875 changed to 32.3465
    • Practice expense RVU 46.06 changed to 43.82

    Held through RVU25B, RVU25C, RVU25D.

  3. March 9, 2024

    RVU24AR

    $1933.39changed to$1965.47

    • Conversion factor 32.7442 changed to 33.2875

    Held through RVU24B, RVU24C, RVU24D.

  4. January 1, 2024

    RVU24A

    $2041.69changed to$1933.39

    • Conversion factor 33.8872 changed to 32.7442
    • Practice expense RVU 47.58 changed to 46.06
    • Malpractice RVU 0.35 changed to 0.36
    • Work GPCI 1.039 changed to 1.043
    • Practice expense GPCI 1.207 changed to 1.220
    • Malpractice GPCI 0.815 changed to 0.853

  5. January 1, 2023

    RVU23A

    $2106.40changed to$2041.69

    • Conversion factor 34.6062 changed to 33.8872
    • Practice expense RVU 48.64 changed to 47.58
    • Malpractice RVU 0.34 changed to 0.35
    • Work GPCI 1.036 changed to 1.039
    • Practice expense GPCI 1.194 changed to 1.207
    • Malpractice GPCI 0.776 changed to 0.815

    Held through RVU23B, RVU23C, RVU23D.

  6. January 1, 2022

    RVU22A

    $2270.94changed to$2106.40

    • Conversion factor 34.8931 changed to 34.6062
    • Practice expense RVU 52.17 changed to 48.64

    Held through RVU22B, RVU22C, RVU22D.

  7. January 1, 2021

    RVU21A

    $2226.87changed to$2270.94

    • Conversion factor 36.0896 changed to 34.8931
    • Practice expense RVU 50.34 changed to 52.17
    • Work GPCI 1.031 changed to 1.036
    • Practice expense GPCI 1.170 changed to 1.194
    • Malpractice GPCI 0.854 changed to 0.776

    Held through RVU21B, RVU21C, RVU21D.

  8. January 1, 2020

    RVU20A

    $2267.87changed to$2226.87

    • Conversion factor 36.0391 changed to 36.0896
    • Practice expense RVU 52.44 changed to 50.34
    • Malpractice RVU 0.35 changed to 0.34
    • Work GPCI 1.027 changed to 1.031
    • Practice expense GPCI 1.146 changed to 1.170
    • Malpractice GPCI 0.931 changed to 0.854

    Held through RVU20B, RVU20C, RVU20D.

  9. January 1, 2019

    RVU19A

    $2324.87changed to$2267.87

    • Conversion factor 35.9996 changed to 36.0391
    • Practice expense RVU 53.89 changed to 52.44
    • Malpractice RVU 0.34 changed to 0.35

    Held through RVU19B, RVU19C, RVU19D.

  10. January 1, 2018

    RVU18AR1

    $2353.26changed to$2324.87

    • Conversion factor 35.8887 changed to 35.9996
    • Work RVU 2.64 changed to 2.44
    • Practice expense RVU 54.38 changed to 53.89
    • Malpractice RVU 0.38 changed to 0.34
    • Work GPCI 1.026 changed to 1.027
    • Practice expense GPCI 1.151 changed to 1.146
    • Malpractice GPCI 0.713 changed to 0.931

    Held through RVU18B, RVU18C, RVU18D.

  11. January 1, 2017

    RVU17A

    $2395.87changed to$2353.26

    • Conversion factor 35.8043 changed to 35.8887
    • Practice expense RVU 55.43 changed to 54.38
    • Work GPCI 1.025 changed to 1.026
    • Practice expense GPCI 1.155 changed to 1.151
    • Malpractice GPCI 0.495 changed to 0.713

    Held through RVU17B, RVU17C, RVU17D.

  12. January 1, 2016

    RVU16A

    $2390.82changed to$2395.87

    • Conversion factor 35.9335 changed to 35.8043
    • Practice expense RVU 55.10 changed to 55.43

    Held through RVU16B, RVU16C, RVU16D.

  13. July 1, 2015

    RVU15C

    $2378.92changed to$2390.82

    • Conversion factor 35.7547 changed to 35.9335

    Held through RVU15D.

  14. January 1, 2015

    RVU15A

    $2398.46changed to$2378.92

    • Conversion factor 35.8228 changed to 35.7547
    • Practice expense RVU 55.67 changed to 55.10
    • Malpractice RVU 0.33 changed to 0.38
    • Practice expense GPCI 1.150 changed to 1.155
    • Malpractice GPCI 0.688 changed to 0.495

    Held through RVU15B.

  15. January 1, 2014

    RVU14A

    $2541.13changed to$2398.46

    • Conversion factor 34.0230 changed to 35.8228
    • Practice expense RVU 62.66 changed to 55.67
    • Malpractice RVU 0.34 changed to 0.33
    • Practice expense GPCI 1.144 changed to 1.150
    • Malpractice GPCI 0.881 changed to 0.688

    Held through RVU14B, RVU14C, RVU14D.

  16. January 1, 2013

    RVU13AR

    Earliest loaded release: $2541.13

    Held through RVU13B, RVU13C, RVU13D.

Rates in every CMS release
Effective fromOfficeFacilityCMS release
2026-10-01$1,900.64$132.64RVU26D
2026-07-01$1,900.64$132.64RVU26C
2026-04-01$1,900.64$132.64RVU26B
2026-01-01$1,900.64$132.64RVU26A
2025-10-01$1,821.51$152.24RVU25D
2025-07-01$1,821.51$152.24RVU25C
2025-04-01$1,821.51$152.24RVU25B
2025-01-01$1,821.51$152.24RVU25A
2024-10-01$1,965.47$155.85RVU24D
2024-07-01$1,965.47$155.85RVU24C
2024-04-01$1,965.47$155.85RVU24B
2024-03-09$1,965.47$155.85RVU24AR
2024-01-01$1,933.39$153.31RVU24A
2023-10-01$2,041.69$156.52RVU23D
2023-07-01$2,041.69$156.52RVU23C
2023-04-01$2,041.69$156.52RVU23B
2023-01-01$2,041.69$156.52RVU23A
2022-10-01$2,106.40$155.70RVU22D
2022-07-01$2,106.40$155.70RVU22C
2022-04-01$2,106.40$155.70RVU22B
2022-01-01$2,106.40$155.70RVU22A
2021-10-01$2,270.94$154.90RVU21D
2021-07-01$2,270.94$154.90RVU21C
2021-04-01$2,270.94$154.90RVU21B
2021-01-01$2,270.94$154.90RVU21A
2020-10-01$2,226.87$157.85RVU20D
2020-07-01$2,226.87$157.85RVU20C
2020-04-01$2,226.87$157.85RVU20B
2020-01-01$2,226.87$157.85RVU20A
2019-10-01$2,267.87$157.81RVU19D
2019-07-01$2,267.87$157.81RVU19C
2019-04-01$2,267.87$157.81RVU19B
2019-01-01$2,267.87$157.81RVU19A
2018-10-01$2,324.87$156.48RVU18D
2018-07-01$2,324.87$156.48RVU18C
2018-04-01$2,324.87$156.48RVU18B
2018-01-01$2,324.87$156.48RVU18AR1
2017-10-01$2,353.26$172.20RVU17D
2017-07-01$2,353.26$172.20RVU17C
2017-04-01$2,353.26$172.20RVU17B
2017-01-01$2,353.26$172.20RVU17A
2016-10-01$2,395.87$170.61RVU16D
2016-07-01$2,395.87$170.61RVU16C
2016-04-01$2,395.87$170.61RVU16B
2016-01-01$2,395.87$170.61RVU16A
2015-10-01$2,390.82$174.14RVU15D
2015-07-01$2,390.82$174.14RVU15C
2015-04-01$2,378.92$173.27RVU15B
2015-01-01$2,378.92$173.27RVU15A
2014-10-01$2,398.46$177.16RVU14D
2014-07-01$2,398.46$177.16RVU14C
2014-04-01$2,398.46$177.16RVU14B
2014-01-01$2,398.46$177.16RVU14A
2013-10-01$2,541.13$176.99RVU13D
2013-07-01$2,541.13$176.99RVU13C
2013-04-01$2,541.13$176.99RVU13B
2013-01-01$2,541.13$176.99RVU13AR

Price 31297 for an earlier date of service

Where the King County, WA rate applies

King County, WA is a Medicare payment area, not a city. Our Census mapping connects it to 63 cities and communities in Washington. Some span more than one payment area; confirm with the service ZIP.

  • Seattle
  • Algona
  • Ames Lake
  • 31297 in Auburn · multiple payment areas
  • Baring
  • Beaux Arts Village
  • Bellevue
  • Black Diamond

Browse all communities in Washington

31297 billing questions

How does 31297 differ from sphenoidotomy code 31287?

Use 31297 for dilation of the sphenoid sinus opening. Code 31287 describes endoscopic sphenoidotomy rather than ostial dilation.

Does 31297 include fluoroscopy?

Yes. Fluoroscopy, when performed as part of the sphenoid ostial dilation, is included in this service.

When is modifier 50 appropriate?

Use modifier 50 when the surgeon dilates both sphenoid sinus ostia. CMS pays the bilateral procedure at 150%.

What happens when another related sinus endoscopy is performed in the same session?

CMS endoscopy family pricing applies when related endoscopies are performed together. The operative documentation should support each distinct sinus procedure reported.

Can an assistant surgeon be reported?

Assistant-at-surgery payment is available only when the documentation establishes medical necessity. Co-surgeons and team surgery are not permitted for this code.

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
RVUs for 31297PPRRVU2026_Oct_nonQPP.csv, line 3,552 (RVU26D)
Geographic factors for King County, WAGPCI2026.csv, line 108 (RVU26D)

Open CMS sourceHow we calculate rates

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