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CPT code 45331: Sigmoidoscopy, with biopsy2026 Medicare rate & RVUs in Chicago, IL

Reports flexible sigmoidoscopy with one or more tissue biopsies when a clinician samples the rectum or distal colon for diagnosis.

CMS RVU26DEffective Oct 1, 2026One payment locality35.9K Medicare services in 2024

In Chicago, IL, Medicare pays $330.71 for 45331 in the office and $73.24 when it’s performed in a hospital or facility.

$330.71Office (non-facility)
$73.24Hospital or facility
+2.4%vs the national office rate ($322.99)

Check a contract rate as a % of Medicare · 45331 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 45331 for the payment locality that covers the ZIP.

On this page 11 sections
  1. Rate in Chicago, IL
  2. What 45331 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 45331 covers

A clinician advances a flexible endoscope through the anus to examine the rectum and distal colon, then collects mucosal tissue for analysis. Gastroenterologists and colorectal surgeons commonly perform this service in an endoscopy unit, hospital outpatient department, or office. Typical reasons include evaluating suspected colitis, unexplained rectal bleeding, or an abnormality seen on prior testing. The biopsy may involve one or multiple tissue samples during the same examination.

Report this code when the procedure includes tissue biopsy, rather than inspection alone; the number of samples does not determine separate units. The record should identify the sampled site and clinical reason, and support that tissue was obtained. The service has a 0-day global period, so same-day preoperative and postoperative care is included. When related endoscopies are performed together, CMS endoscopy-family pricing applies. Modifier 50 is inappropriate. Medicare does not pay an assistant at surgery for this service, and co-surgeon and team-surgery billing 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 Chicago, IL compares for 45331

Across 109 of 109 payment localities, the office rate for 45331 runs from $281.06 in Arkansas to $449.20 in San Benito County, CA. Chicago, IL pays $330.71. The RVUs are the same everywhere; the geographic indexes change the dollars.

45331 in Chicago, IL vs other payment areas
  1. Chicago, IL · this page$330.71
  2. East St. Louis, IL · Illinois$305.23−$25.48
  3. Rest of Illinois · Illinois$301.15−$29.56
  4. Suburban Chicago, IL · Illinois$334.45+$3.74
  5. Los Angeles, CA · California$374.40+$43.69
  6. Washington, DC area · District of Columbia$375.58+$44.87
  7. Miami, FL · Florida$341.67+$10.96

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

Every other payment area

45331 in every other Medicare payment locality
Payment localityOfficeFacility
Manhattan, NYNew York$373.66$75.97
AlaskaAlaska$357.70$84.87
AlabamaAlabama$285.80$61.64
ArkansasArkansas$281.06$61.00
ArizonaArizona$313.60$65.35
Bakersfield, CACalifornia$348.86$68.08
Chico, CACalifornia$348.45$67.67
El Centro, CACalifornia$348.47$67.69

45331 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.

$281.06

$398.83

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

View every state and territory as a table
45331 office rate range by state
State / territoryOffice rate rangeLocalities
AK$357.701
AL$285.801
AR$281.061
AZ$313.601
CA$348.45–$449.2029
CO$340.411
CT$346.371
DC$375.581
DE$319.321
FL$312.96–$341.673
GA$293.51–$328.542
GU$359.551
HI$359.551
IA$296.261
ID$298.021
IL$301.15–$334.454
IN$300.051
KS$293.671
KY$291.371
LA$290.45–$307.032
MA$337.54–$378.552
MD$326.35–$375.583
ME$298.72–$318.732
MI$299.12–$316.352
MN$327.851
MO$284.05–$309.503
MS$282.671
MT$322.981
NC$302.461
ND$320.211
NE$298.421
NH$333.931
NJ$350.80–$370.642
NM$300.581
NV$322.491
NY$307.54–$382.525
OH$298.561
OK$291.851
OR$320.47–$353.602
PA$299.67–$336.092
PR$326.011
RI$332.471
SC$300.911
SD$319.881
TN$295.231
TX$297.34–$338.848
UT$305.641
VA$316.83–$375.582
VI$326.011
VT$317.861
WA$337.26–$387.832
WI$307.941
WV$288.161
WY$321.771

See 45331 in every payment locality

How the 45331 rate is calculated

Each of 45331’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 · 45331

RVUs × geographic indexes × conversion factor

Office or facility?

Work1.11

1.11 RVUs× 1.000 GPCI

Practice expense8.42

8.42 RVUs× 1.000 GPCI

Malpractice0.14

0.14 RVUs× 1.000 GPCI

Adjusted RVUs

9.6700

Conversion factor

$33.4009

Medicare rate

$322.99

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

The exact Chicago, IL inputs and CMS source lines

PPRRVU2026_Oct_nonQPP.csv

5,499

Code
45331
Physician work
1.11
Practice expense
8.42
Malpractice
0.14

GPCI2026.csv

48

Locality
Chicago, IL
Physician work
1.007
Practice expense
1.005
Malpractice
2.295
Office calculation for 45331 in Chicago, IL
ComponentRVULocality factorAdjusted
Physician work1.11× 1.0071.1178
Practice expense8.42× 1.0058.4621
Malpractice0.14× 2.2950.3213
Total RVUs9.9012
Conversion factor× 33.4009

Office rate, Chicago, IL$330.71

Office: (1.11 × 1.007 + 8.42 × 1.005 + 0.14 × 2.295) × $33.4009 = $330.71

Facility: (1.11 × 1.007 + 0.75 × 1.005 + 0.14 × 2.295) × $33.4009 = $73.24

Open 45331 in the RVU calculator

Payment rules and modifiers for 45331

The CMS indicators that decide how 45331 is paid alongside other services.

CMS payment indicators · 45331

Sigmoidoscopy, with biopsy

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)0The 150% bilateral adjustment doesn’t apply.
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

45331 without 51 · national office

$322.99

Sigmoidoscopy, with biopsy

45331-51 · Second procedure: 50%

$161.50

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 45331

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

Codes related to 45331
CodeHow it relatesOffice range, Chicago, IL
Same family
45330Flexible sigmoidoscopy, diagnosticFlexible sigmoidoscopy for diagnostic inspection without biopsy or another intervention.$221.40
45333Flexible sigmoidoscopy, hot biopsy forceps removalFlexible sigmoidoscopy with polyp removal rather than tissue sampling alone.$379.50
Used instead
45305Proctosigmoidoscopy, rigid scope with biopsyBiopsy during proctosigmoidoscopy, using a different endoscopic examination.$208.09
45342Sigmoidoscopy, ultrasound-guided tissue samplingBiopsy performed with endoscopic ultrasound guidance during sigmoidoscopy.No office rate

How 45331 has changed in Chicago, IL

45331 · Office / nonfacility

$330.71

Effective 2026-10-01

The base rate is $47.86 higher than on 2025-10-01, moving from $282.85 to $330.71 (16.9%).

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

    $282.85changed to$330.71

    • Conversion factor 32.3465 changed to 33.4009
    • Work RVU 1.14 changed to 1.11
    • Practice expense RVU 7.11 changed to 8.42
    • Malpractice RVU 0.16 changed to 0.14
    • Practice expense GPCI 1.023 changed to 1.005
    • Malpractice GPCI 2.018 changed to 2.295

    Held through RVU26B, RVU26C, RVU26D.

  2. January 1, 2025

    RVU25A

    $296.54changed to$282.85

    • Conversion factor 33.2875 changed to 32.3465
    • Practice expense RVU 7.29 changed to 7.11
    • Malpractice RVU 0.15 changed to 0.16

    Held through RVU25B, RVU25C, RVU25D.

  3. March 9, 2024

    RVU24AR

    $291.70changed to$296.54

    • Conversion factor 32.7442 changed to 33.2875

    Held through RVU24B, RVU24C, RVU24D.

  4. January 1, 2024

    RVU24A

    $305.50changed to$291.70

    • Conversion factor 33.8872 changed to 32.7442
    • Practice expense RVU 7.35 changed to 7.29
    • Malpractice RVU 0.14 changed to 0.15
    • Work GPCI 1.009 changed to 1.007
    • Practice expense GPCI 1.033 changed to 1.023
    • Malpractice GPCI 1.945 changed to 2.018

  5. January 1, 2023

    RVU23A

    $321.51changed to$305.50

    • Conversion factor 34.6062 changed to 33.8872
    • Practice expense RVU 7.58 changed to 7.35
    • Malpractice RVU 0.12 changed to 0.14
    • Work GPCI 1.011 changed to 1.009
    • Practice expense GPCI 1.044 changed to 1.033
    • Malpractice GPCI 1.871 changed to 1.945

    Held through RVU23B, RVU23C, RVU23D.

  6. January 1, 2022

    RVU22A

    $322.57changed to$321.51

    • Conversion factor 34.8931 changed to 34.6062
    • Practice expense RVU 7.50 changed to 7.58
    • Malpractice RVU 0.14 changed to 0.12

    Held through RVU22B, RVU22C, RVU22D.

  7. January 1, 2021

    RVU21A

    $296.40changed to$322.57

    • Conversion factor 36.0896 changed to 34.8931
    • Practice expense RVU 6.56 changed to 7.50
    • Malpractice RVU 0.13 changed to 0.14
    • Work GPCI 1.009 changed to 1.011
    • Practice expense GPCI 1.039 changed to 1.044
    • Malpractice GPCI 1.898 changed to 1.871

    Held through RVU21B, RVU21C, RVU21D.

  8. January 1, 2020

    RVU20A

    $286.96changed to$296.40

    • Conversion factor 36.0391 changed to 36.0896
    • Practice expense RVU 6.31 changed to 6.56
    • Malpractice RVU 0.15 changed to 0.13
    • Work GPCI 1.008 changed to 1.009
    • Practice expense GPCI 1.034 changed to 1.039
    • Malpractice GPCI 1.925 changed to 1.898

    Held through RVU20B, RVU20C, RVU20D.

  9. January 1, 2019

    RVU19A

    $277.71changed to$286.96

    • Conversion factor 35.9996 changed to 36.0391
    • Practice expense RVU 6.07 changed to 6.31

    Held through RVU19B, RVU19C, RVU19D.

  10. January 1, 2018

    RVU18AR1

    $274.36changed to$277.71

    • Conversion factor 35.8887 changed to 35.9996
    • Practice expense RVU 5.98 changed to 6.07
    • Work GPCI 1.012 changed to 1.008
    • Practice expense GPCI 1.036 changed to 1.034
    • Malpractice GPCI 1.972 changed to 1.925

    Held through RVU18B, RVU18C, RVU18D.

  11. January 1, 2017

    RVU17A

    $274.35changed to$274.36

    • Conversion factor 35.8043 changed to 35.8887
    • Work GPCI 1.016 changed to 1.012
    • Practice expense GPCI 1.037 changed to 1.036
    • Malpractice GPCI 2.019 changed to 1.972

    Held through RVU17B, RVU17C, RVU17D.

  12. January 1, 2016

    RVU16A

    $178.03changed to$274.35

    • Conversion factor 35.9335 changed to 35.8043
    • Work RVU 1.15 changed to 1.14
    • Practice expense RVU 3.32 changed to 5.98
    • Malpractice RVU 0.17 changed to 0.15

    Held through RVU16B, RVU16C, RVU16D.

  13. July 1, 2015

    RVU15C

    $177.15changed to$178.03

    • Conversion factor 35.7547 changed to 35.9335

    Held through RVU15D.

  14. January 1, 2015

    RVU15A

    $178.03changed to$177.15

    • Conversion factor 35.8228 changed to 35.7547
    • Practice expense RVU 3.30 changed to 3.32
    • Work GPCI 1.023 changed to 1.016
    • Practice expense GPCI 1.044 changed to 1.037
    • Malpractice GPCI 2.048 changed to 2.019

    Held through RVU15B.

  15. January 1, 2014

    RVU14A

    $189.26changed to$178.03

    • Conversion factor 34.0230 changed to 35.8228
    • Practice expense RVU 3.81 changed to 3.30
    • Malpractice RVU 0.18 changed to 0.17
    • Work GPCI 1.030 changed to 1.023
    • Practice expense GPCI 1.051 changed to 1.044
    • Malpractice GPCI 2.077 changed to 2.048

    Held through RVU14B, RVU14C, RVU14D.

  16. October 1, 2013

    RVU13D

    No ratechanged to$189.26

  17. January 1, 2013

    RVU13AR

    Earliest loaded release: No rate

    Held through RVU13B, RVU13C.

Rates in every CMS release
Effective fromOfficeFacilityCMS release
2026-10-01$330.71$73.24RVU26D
2026-07-01$330.71$73.24RVU26C
2026-04-01$330.71$73.24RVU26B
2026-01-01$330.71$73.24RVU26A
2025-10-01$282.85$76.37RVU25D
2025-07-01$282.85$76.37RVU25C
2025-04-01$282.85$76.37RVU25B
2025-01-01$282.85$76.37RVU25A
2024-10-01$296.54$77.58RVU24D
2024-07-01$296.54$77.58RVU24C
2024-04-01$296.54$77.58RVU24B
2024-03-09$296.54$77.58RVU24AR
2024-01-01$291.70$76.31RVU24A
2023-10-01$305.50$77.61RVU23D
2023-07-01$305.50$77.61RVU23C
2023-04-01$305.50$77.61RVU23B
2023-01-01$305.50$77.61RVU23A
2022-10-01$321.51$77.64RVU22D
2022-07-01$321.51$77.64RVU22C
2022-04-01$321.51$77.64RVU22B
2022-01-01$321.51$77.64RVU22A
2021-10-01$322.57$78.86RVU21D
2021-07-01$322.57$78.86RVU21C
2021-04-01$322.57$78.86RVU21B
2021-01-01$322.57$78.86RVU21A
2020-10-01$296.40$80.04RVU20D
2020-07-01$296.40$80.04RVU20C
2020-04-01$296.40$80.04RVU20B
2020-01-01$296.40$80.04RVU20A
2019-10-01$286.96$81.26RVU19D
2019-07-01$286.96$81.26RVU19C
2019-04-01$286.96$81.26RVU19B
2019-01-01$286.96$81.26RVU19A
2018-10-01$277.71$81.91RVU18D
2018-07-01$277.71$81.91RVU18C
2018-04-01$277.71$81.91RVU18B
2018-01-01$277.71$81.91RVU18AR1
2017-10-01$274.36$82.51RVU17D
2017-07-01$274.36$82.51RVU17C
2017-04-01$274.36$82.51RVU17B
2017-01-01$274.36$82.51RVU17A
2016-10-01$274.35$82.39RVU16D
2016-07-01$274.35$82.39RVU16C
2016-04-01$274.35$82.39RVU16B
2016-01-01$274.35$82.39RVU16A
2015-10-01$178.03$85.62RVU15D
2015-07-01$178.03$85.62RVU15C
2015-04-01$177.15$85.19RVU15B
2015-01-01$177.15$85.19RVU15A
2014-10-01$178.03$86.03RVU14D
2014-07-01$178.03$86.03RVU14C
2014-04-01$178.03$86.03RVU14B
2014-01-01$178.03$86.03RVU14A
2013-10-01$189.26$87.35RVU13D
2013-07-01Rate data unavailableRate data unavailableRVU13C
2013-04-01Rate data unavailableRate data unavailableRVU13B
2013-01-01Rate data unavailableRate data unavailableRVU13AR

Price 45331 for an earlier date of service

Where the Chicago, IL rate applies

Chicago, IL is a Medicare payment area, not a city. Our Census mapping connects it to 137 cities and communities in Illinois. Some span more than one payment area; confirm with the service ZIP.

Browse all communities in Illinois

45331 billing questions

How does this differ from diagnostic sigmoidoscopy?

Use 45331 when the flexible examination includes tissue sampling. Use 45330 when the examination is diagnostic without biopsy or another reportable intervention.

Can multiple biopsy samples be reported as multiple units?

No. The code covers one or multiple biopsies during the sigmoidoscopy; the number of specimens alone does not create additional units.

Can the biopsy and a polypectomy be reported together?

A biopsy that is simply part of removing the same lesion should not be represented separately as a diagnostic biopsy. Distinct sampling or treatment requires documentation of what was done and where.

Should modifier 50 be used for biopsies on both sides?

No. CMS identifies bilateral adjustment as inappropriate for this code, and modifier 50 should not be used.

Is same-day care included in the payment?

Yes. The 0-day global period includes same-day preoperative and postoperative care.

Can an assistant surgeon or co-surgeon be billed?

Medicare does not pay an assistant at surgery for this service. Co-surgeon and team-surgery billing are not permitted.

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 45331PPRRVU2026_Oct_nonQPP.csv, line 5,499 (RVU26D)
Geographic factors for Chicago, ILGPCI2026.csv, line 48 (RVU26D)

Open CMS sourceHow we calculate rates

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