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CPT code 31231: Nasal endoscopy, diagnostic, without sinusoscopy2026 Medicare rate & RVUs in King County, WA

Report diagnostic nasal endoscopy for endoscopic inspection of the nasal passages, meatuses, and sphenoethmoid recess without sinus entry or surgical treatment.

CMS RVU26DEffective Oct 1, 2026One payment locality739.4K Medicare services in 2024

In King County, WA, Medicare pays $228.77 for 31231 in the office and $58.70 when it’s performed in a hospital or facility.

$228.77Office (non-facility)
$58.70Hospital or facility
+18.3%vs the national office rate ($193.39)

Check a contract rate as a % of Medicare · 31231 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 31231 for the payment locality that covers the ZIP.

On this page 11 sections
  1. Rate in King County, WA
  2. What 31231 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 31231 covers

An otolaryngologist, and sometimes an allergist or advanced practice provider, uses a rigid or flexible scope to inspect the nasal cavity in an office or outpatient facility. Topical decongestant or anesthetic may be used. The examination can show the septum, turbinates, middle meatus, sphenoethmoid recess, and nasopharynx when visualized. Common indications include chronic rhinosinusitis, nasal obstruction, recurrent epistaxis, suspected polyps or masses, and surveillance after sinus surgery when no debridement is performed.

Report one unit whether one or both sides are examined; the code is already priced as bilateral, so modifier 50 adds no payment. Document the indication, sides examined, structures viewed, and findings. Its 0-day global period includes same-day pre- and post-procedure care. A separately identifiable E/M service beyond that care may be reported with modifier 25 on the E/M code. For multiple procedures in the same session, the highest-valued is paid in full and other procedures subject to the standard reduction are paid at 50%. Medicare does not pay an assistant at surgery or permit co-surgeons or team surgery for this code.

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 31231

Across 109 of 109 payment localities, the office rate for 31231 runs from $169.32 in Arkansas to $262.16 in San Benito County, CA. King County, WA pays $228.77. The RVUs are the same everywhere; the geographic indexes change the dollars.

31231 in King County, WA vs other payment areas
  1. King County, WA · this page$228.77
  2. Rest of Washington · Washington$200.65−$28.12
  3. Los Angeles, CA · California$220.93−$7.84
  4. Washington, DC area · District of Columbia$223.04−$5.73
  5. Miami, FL · Florida$207.81−$20.96
  6. Chicago, IL · Illinois$201.32−$27.45
  7. Manhattan, NY · New York$223.48−$5.29

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

Every other payment area

31231 in every other Medicare payment locality
Payment localityOfficeFacility
AlaskaAlaska$218.76$71.14
AlabamaAlabama$172.03$50.75
ArkansasArkansas$169.32$50.25
ArizonaArizona$187.90$53.58
Bakersfield, CACalifornia$206.60$54.68
Chico, CACalifornia$206.14$54.22
El Centro, CACalifornia$206.17$54.25
Fresno, CACalifornia$206.14$54.22

31231 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.

$169.32

$234.15

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

View every state and territory as a table
31231 office rate range by state
State / territoryOffice rate rangeLocalities
AK$218.761
AL$172.031
AR$169.321
AZ$187.901
CA$206.14–$262.1629
CO$202.401
CT$206.961
DC$223.041
DE$191.201
FL$189.38–$207.813
GA$177.97–$197.012
GU$212.011
HI$212.011
IA$177.221
ID$178.391
IL$183.15–$201.884
IN$179.531
KS$176.121
KY$176.031
LA$175.65–$185.132
MA$200.95–$223.822
MD$195.14–$223.043
ME$179.19–$190.052
MI$180.83–$191.732
MN$194.051
MO$172.23–$186.093
MS$170.831
MT$193.381
NC$181.261
ND$190.221
NE$178.341
NH$198.971
NJ$209.35–$220.382
NM$181.821
NV$192.651
NY$184.19–$229.045
OH$180.181
OK$175.901
OR$191.19–$209.502
PA$180.61–$201.312
PR$194.991
RI$198.521
SC$181.011
SD$189.841
TN$177.061
TX$179.30–$201.698
UT$183.711
VA$189.23–$223.042
VI$194.991
VT$189.231
WA$200.65–$228.772
WI$183.301
WV$175.741
WY$192.001

See 31231 in every payment locality

How the 31231 rate is calculated

Each of 31231’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 · 31231

RVUs × geographic indexes × conversion factor

Office or facility?

Work1.07

1.07 RVUs× 1.000 GPCI

Practice expense4.56

4.56 RVUs× 1.000 GPCI

Malpractice0.16

0.16 RVUs× 1.000 GPCI

Adjusted RVUs

5.7900

Conversion factor

$33.4009

Medicare rate

$193.39

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

3,524

Code
31231
Physician work
1.07
Practice expense
4.56
Malpractice
0.16

GPCI2026.csv

108

Locality
King County, WA
Physician work
1.050
Practice expense
1.227
Malpractice
0.817
Office calculation for 31231 in King County, WA
ComponentRVULocality factorAdjusted
Physician work1.07× 1.0501.1235
Practice expense4.56× 1.2275.5951
Malpractice0.16× 0.8170.1307
Total RVUs6.8493
Conversion factor× 33.4009

Office rate, King County, WA$228.77

Office: (1.07 × 1.05 + 4.56 × 1.227 + 0.16 × 0.817) × $33.4009 = $228.77

Facility: (1.07 × 1.05 + 0.41 × 1.227 + 0.16 × 0.817) × $33.4009 = $58.70

Open 31231 in the RVU calculator

Payment rules and modifiers for 31231

The CMS indicators that decide how 31231 is paid alongside other services.

CMS payment indicators · 31231

Nasal endoscopy, diagnostic, without sinusoscopy

RuleCMS valueWhat it means
Global period000Same-day global: pre- and post-op care on the day of the procedure is included.
Multiple procedures2Standard reduction: highest-valued procedure at 100%, others at 50%.
Bilateral (modifier 50)2Already bilateral by definition: paid once at 100%.
Assistant at surgery (80/81/82/AS)1Not paid (statutory restriction).
Co-surgeons (62)0Not permitted.
Team surgery (66)0Not permitted.
Professional/technical0Physician service: no professional/technical split.

What modifiers do to the payment

Modifier 51 · payment effect

With and without the modifier

31231 without 51 · national office

$193.39

Nasal endoscopy, diagnostic, without sinusoscopy

31231-51 · Second procedure: 50%

$96.70

When this isn’t the highest-valued procedure in the session, Medicare pays 50% of its fee schedule amount (the highest is paid at 100%).

When to use modifier 51

Codes related to 31231

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

Codes related to 31231
CodeHow it relatesOffice range, King County, WA
Same family
31233Sinus endoscopy, maxillary sinusDiagnostic endoscopy that includes direct examination inside the maxillary sinus.$317.72
31235Sinus endoscopy, diagnostic sphenoid sinusoscopyDiagnostic endoscopy that includes direct examination inside the sphenoid sinus.$360.47
31237Nasal endoscopy, biopsy, polypectomy, or debridementSurgical nasal or sinus endoscopy with biopsy, polyp removal, or debridement.$306.96
31238Nasal endoscopy, hemorrhage controlSurgical nasal endoscopy that treats bleeding rather than only inspecting the nasal cavity.$298.13
Used instead
92511Nasopharyngoscopy, endoscopic nasopharynx examNasopharyngoscopy when the nasopharynx, rather than nasal cavity structures, is the examination's focus.$138.17
Often billed with
99213Office visit, established patient, low complexityEstablished-patient E/M when that level is supported and the service is separately identifiable; append modifier 25.$107.88

How 31231 has changed in King County, WA

31231 · Office / nonfacility

$228.77

Effective 2026-10-01

The base rate is $12.42 higher than on 2025-10-01, moving from $216.35 to $228.77 (5.7%).

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

    $216.35changed to$228.77

    • Conversion factor 32.3465 changed to 33.4009
    • Work RVU 1.10 changed to 1.07
    • Practice expense RVU 4.43 changed to 4.56
    • 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

    $220.20changed to$216.35

    • Conversion factor 33.2875 changed to 32.3465
    • Practice expense RVU 4.37 changed to 4.43

    Held through RVU25B, RVU25C, RVU25D.

  3. March 9, 2024

    RVU24AR

    $216.61changed to$220.20

    • Conversion factor 32.7442 changed to 33.2875

    Held through RVU24B, RVU24C, RVU24D.

  4. January 1, 2024

    RVU24A

    $224.62changed to$216.61

    • Conversion factor 33.8872 changed to 32.7442
    • Practice expense RVU 4.43 changed to 4.37
    • Malpractice RVU 0.17 changed to 0.16
    • 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

    $225.83changed to$224.62

    • Conversion factor 34.6062 changed to 33.8872
    • Practice expense RVU 4.42 changed to 4.43
    • Malpractice RVU 0.14 changed to 0.17
    • 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

    $232.97changed to$225.83

    • Conversion factor 34.8931 changed to 34.6062
    • Practice expense RVU 4.54 changed to 4.42
    • Malpractice RVU 0.15 changed to 0.14

    Held through RVU22B, RVU22C, RVU22D.

  7. January 1, 2021

    RVU21A

    $224.39changed to$232.97

    • Conversion factor 36.0896 changed to 34.8931
    • Practice expense RVU 4.25 changed to 4.54
    • Malpractice RVU 0.13 changed to 0.15
    • 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

    $229.04changed to$224.39

    • Conversion factor 36.0391 changed to 36.0896
    • Practice expense RVU 4.43 changed to 4.25
    • Malpractice RVU 0.16 changed to 0.13
    • 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

    $239.93changed to$229.04

    • Conversion factor 35.9996 changed to 36.0391
    • Practice expense RVU 4.70 changed to 4.43

    Held through RVU19B, RVU19C, RVU19D.

  10. January 1, 2018

    RVU18AR1

    $237.25changed to$239.93

    • Conversion factor 35.8887 changed to 35.9996
    • Practice expense RVU 4.67 changed to 4.70
    • Malpractice RVU 0.15 changed to 0.16
    • 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

    $239.46changed to$237.25

    • Conversion factor 35.8043 changed to 35.8887
    • Practice expense RVU 4.75 changed to 4.67
    • 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

    $238.84changed to$239.46

    • Conversion factor 35.9335 changed to 35.8043
    • Practice expense RVU 4.71 changed to 4.75
    • Malpractice RVU 0.16 changed to 0.15

    Held through RVU16B, RVU16C, RVU16D.

  13. July 1, 2015

    RVU15C

    $237.65changed to$238.84

    • Conversion factor 35.7547 changed to 35.9335

    Held through RVU15D.

  14. January 1, 2015

    RVU15A

    $237.14changed to$237.65

    • Conversion factor 35.8228 changed to 35.7547
    • Malpractice RVU 0.11 changed to 0.16
    • 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

    $244.74changed to$237.14

    • Conversion factor 34.0230 changed to 35.8228
    • Practice expense RVU 5.21 changed to 4.71
    • Malpractice RVU 0.12 changed to 0.11
    • 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: $244.74

    Held through RVU13B, RVU13C, RVU13D.

Rates in every CMS release
Effective fromOfficeFacilityCMS release
2026-10-01$228.77$58.70RVU26D
2026-07-01$228.77$58.70RVU26C
2026-04-01$228.77$58.70RVU26B
2026-01-01$228.77$58.70RVU26A
2025-10-01$216.35$67.97RVU25D
2025-07-01$216.35$67.97RVU25C
2025-04-01$216.35$67.97RVU25B
2025-01-01$216.35$67.97RVU25A
2024-10-01$220.20$69.94RVU24D
2024-07-01$220.20$69.94RVU24C
2024-04-01$220.20$69.94RVU24B
2024-03-09$220.20$69.94RVU24AR
2024-01-01$216.61$68.80RVU24A
2023-10-01$224.62$70.42RVU23D
2023-07-01$224.62$70.42RVU23C
2023-04-01$224.62$70.42RVU23B
2023-01-01$224.62$70.42RVU23A
2022-10-01$225.83$69.23RVU22D
2022-07-01$225.83$69.23RVU22C
2022-04-01$225.83$69.23RVU22B
2022-01-01$225.83$69.23RVU22A
2021-10-01$232.97$69.24RVU21D
2021-07-01$232.97$69.24RVU21C
2021-04-01$232.97$69.24RVU21B
2021-01-01$232.97$69.24RVU21A
2020-10-01$224.39$69.85RVU20D
2020-07-01$224.39$69.85RVU20C
2020-04-01$224.39$69.85RVU20B
2020-01-01$224.39$69.85RVU20A
2019-10-01$229.04$70.86RVU19D
2019-07-01$229.04$70.86RVU19C
2019-04-01$229.04$70.86RVU19B
2019-01-01$229.04$70.86RVU19A
2018-10-01$239.93$70.37RVU18D
2018-07-01$239.93$70.37RVU18C
2018-04-01$239.93$70.37RVU18B
2018-01-01$239.93$70.37RVU18AR1
2017-10-01$237.25$69.54RVU17D
2017-07-01$237.25$69.54RVU17C
2017-04-01$237.25$69.54RVU17B
2017-01-01$237.25$69.54RVU17A
2016-10-01$239.46$68.67RVU16D
2016-07-01$239.46$68.67RVU16C
2016-04-01$239.46$68.67RVU16B
2016-01-01$239.46$68.67RVU16A
2015-10-01$238.84$69.09RVU15D
2015-07-01$238.84$69.09RVU15C
2015-04-01$237.65$68.75RVU15B
2015-01-01$237.65$68.75RVU15A
2014-10-01$237.14$69.47RVU14D
2014-07-01$237.14$69.47RVU14C
2014-04-01$237.14$69.47RVU14B
2014-01-01$237.14$69.47RVU14A
2013-10-01$244.74$68.81RVU13D
2013-07-01$244.74$68.81RVU13C
2013-04-01$244.74$68.81RVU13B
2013-01-01$244.74$68.81RVU13AR

Price 31231 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
  • 31231 in Auburn · multiple payment areas
  • Baring
  • Beaux Arts Village
  • Bellevue
  • Black Diamond

Browse all communities in Washington

31231 billing questions

Should modifier 50 or RT/LT be added when both sides of the nose are scoped?

No. Report one unit for a bilateral examination without modifier 50 or RT/LT; the code is already priced as bilateral.

Can this code be billed with a surgical sinus endoscopy on the same side?

Do not separately report the diagnostic inspection of the same site during a surgical nasal or sinus endoscopy. Report the applicable surgical code when biopsy, polyp removal, or ethmoidectomy is performed.

When should 31233 or 31235 be reported instead?

Use 31233 for diagnostic maxillary sinusoscopy and 31235 for diagnostic sphenoid sinusoscopy. Inspection of the nasal cavity and sinus openings without entering either sinus remains 31231.

Can an office visit be billed on the same day as the endoscopy?

Yes, if the E/M service is significant and separately identifiable from the routine assessment and same-day care included with the endoscopy. Append modifier 25 to the E/M code.

Does passing a flexible laryngoscope through the nose support a separate nasal endoscopy?

No. Transnasal passage to examine the larynx does not by itself establish a separate diagnostic nasal examination. Report 31231 only when a medically necessary nasal cavity examination is separately performed and documented.

What documentation supports the procedure?

Record the indication, sides examined, structures viewed, and endoscopic findings. Document the scope type and any anesthetic or decongestant used; a note stating only “nasal exam” does not establish the endoscopic examination.

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 31231PPRRVU2026_Oct_nonQPP.csv, line 3,524 (RVU26D)
Geographic factors for King County, WAGPCI2026.csv, line 108 (RVU26D)

Open CMS sourceHow we calculate rates

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