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Billing code 45100: Rectal biopsyMedicare rate & RVUs

Transanal rectal biopsy obtains tissue for diagnosis, including evaluation of suspected Hirschsprung disease when a surgical tissue sample is needed.

CMS RVU26DEffective Oct 1, 2026109 payment localities1.8K Medicare services in 2024

Medicare pays $302.28 for 45100 nationally in a facility.

Medicare rate · 45100

Rectal biopsy

Swap in your local Medicare rate.

Work RVUs
3.94
Total RVUs
9.05
Global days
090

National rate · 2026

$302.28

Facility setting, before claim adjustments.

See every locality for 45100 → · Billed by an NP, PA or therapist? →

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

On this page 10 sections
  1. Medicare rate
  2. What 45100 covers
  3. By payment locality
  4. Rate map
  5. How it’s calculated
  6. Payment rules
  7. Similar codes
  8. Related codes
  9. Billing questions
  10. Sources

What 45100 covers

A surgeon reaches the rectum through the anus and removes tissue for pathologic examination. A common use is obtaining an adequate rectal sample when evaluating suspected Hirschsprung disease; colorectal, general, or pediatric surgeons may perform the procedure in an operating room or ambulatory surgery setting. This is distinct from taking a biopsy through a flexible endoscope.

Report the transanal biopsy when the operative record supports surgical access and tissue sampling from the rectum. Document the indication, approach, biopsy site, and specimens submitted for pathology. The 90-day global period includes the day-before preoperative visit and 90 days of related postoperative care. For other procedures performed in the same session, the highest-valued procedure is paid in full and other procedures are subject to the standard 50% multiple-procedure reduction. Modifier 50 is inappropriate. Medicare does not pay an assistant at surgery for this code; 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 45100 pays more and less

The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.

109 of 109 payment localities

45100 office and facility rates by payment locality
Payment localityOfficeFacility
AlabamaUnavailable$272.89
Alaska*Unavailable$365.78
ArizonaUnavailable$294.04
ArkansasUnavailable$269.25
AtlantaUnavailable$310.22
AustinUnavailable$307.96
BakersfieldUnavailable$308.48
Baltimore/Surr. CntysUnavailable$321.12
BeaumontUnavailable$287.41
BrazoriaUnavailable$296.30

45100 rates by state

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

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Local rates. Clear comparisons.

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

View every state and territory as a table
45100 office rate range by state
State / territoryOffice rate rangeLocalities
AKNo published base rate1
ALNo published base rate1
ARNo published base rate1
AZNo published base rate1
CANo published base rate29
CONo published base rate1
CTNo published base rate1
DCNo published base rate1
DENo published base rate1
FLNo published base rate3
GANo published base rate2
GUNo published base rate1
HINo published base rate1
IANo published base rate1
IDNo published base rate1
ILNo published base rate4
INNo published base rate1
KSNo published base rate1
KYNo published base rate1
LANo published base rate2
MANo published base rate2
MDNo published base rate3
MENo published base rate2
MINo published base rate2
MNNo published base rate1
MONo published base rate3
MSNo published base rate1
MTNo published base rate1
NCNo published base rate1
NDNo published base rate1
NENo published base rate1
NHNo published base rate1
NJNo published base rate2
NMNo published base rate1
NVNo published base rate1
NYNo published base rate5
OHNo published base rate1
OKNo published base rate1
ORNo published base rate2
PANo published base rate2
PRNo published base rate1
RINo published base rate1
SCNo published base rate1
SDNo published base rate1
TNNo published base rate1
TXNo published base rate8
UTNo published base rate1
VANo published base rate2
VINo published base rate1
VTNo published base rate1
WANo published base rate2
WINo published base rate1
WVNo published base rate1
WYNo published base rate1

How the 45100 rate is calculated

Each of 45100’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 · 45100

RVUs × geographic indexes × conversion factor

Swap in your local Medicare rate.

Work 3.94Practice expense 4.33Malpractice 0.78

9.0500 adjusted RVUs×$33.4009 conversion factor=$302.28

All indexes start at 1.000 (the national rate). Enter a ZIP or drag a slider.

Payment rules and modifiers for 45100

45100 has a 90-day global period: related visits in that window are included in the surgery payment.

CMS payment indicators · 45100

Rectal biopsy

RuleCMS valueWhat it means
Global period090Major surgery: the day before, the day of, and 90 days after are included.
Multiple procedures2Standard reduction: highest-valued procedure at 100%, others at 50%.
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.
Split (54/55/56)0.09/0.81/0.10Share of the payment for pre-op, the procedure itself, and post-op care.

Global surgery period · 45100

Rectal biopsy

90-day global period ends

Dec 30, 2026

Covers Sep 30, 2026 through Dec 30, 2026 (92 days, including the day before surgery).

Visit on Oct 31, 2026

Day 30 of the 90-day post-op period: related follow-up care is included in the surgical payment.

  • 24 Unrelated E/M visit by the same physician
  • 79 Unrelated procedure (starts its own global period)
  • 58 Staged, more extensive, or therapy procedure that was planned
  • 78 Unplanned return to the operating room for a related complication
SurgeryVisit
Sep 23, 2026Jan 10, 2027

Pre-op dayGlobal period

What modifiers do to the payment

Modifier 51 · payment effect

With and without the modifier

45100 without 51 · national facility

$302.28

Rectal biopsy

45100-51 · Second procedure: 50%

$151.14

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

45100 compared with similar codes

Compare codes

45100 vs 45331 vs 45380 vs 45160: national Medicare rates

Swap in your local Medicare rate.

  • 45100
    Rectal biopsy · 3.94 wRVU
    —
  • 45331
    Sigmoidoscopy · 1.11 wRVU
    $322.99
  • 45380
    Colonoscopy with biopsy · 3.47 wRVU
    $479.97
  • 45160
    Rectal lesion excision · 15.92 wRVU
    —

How to choose

45331Sigmoidoscopy
Use 45331 when a flexible sigmoidoscope is used to obtain the biopsy. Use 45100 for tissue sampling through transanal surgical access.
45380Colonoscopy with biopsy
Use 45380 for biopsy performed during colonoscopy. The defining distinction is endoscopic access rather than transanal surgical access.
45160Rectal lesion excision
45160 describes transanal excision of a rectal lesion; 45100 describes obtaining biopsy tissue rather than excising the lesion.

Codes related to 45100

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

Codes related to 45100
CodeHow it relatesNational office range
Used instead
45331SigmoidoscopyFlexible sigmoidoscopy with biopsy when tissue is sampled through the endoscope.$281.06–$449.20
45380Colonoscopy with biopsyColonoscopy with biopsy when tissue is sampled through the colonoscope.$423.81–$640.93
45160Rectal lesion excisionTransanal excision of a rectal lesion rather than biopsy alone.No office rate

45100 billing questions

How does this differ from an endoscopic rectal biopsy?

This code describes tissue sampling through transanal surgical access. A biopsy taken through a flexible sigmoidoscope or colonoscope is reported with the applicable endoscopy code instead.

Is this the usual code for a rectal biopsy to evaluate suspected Hirschsprung disease?

It can describe a transanal surgical biopsy obtained for that evaluation. The operative note should establish the transanal approach and rectal tissue sampling.

Can modifier 50 be used for biopsies on both sides?

No. CMS identifies bilateral adjustment as inappropriate for this code; do not append modifier 50.

How does the 90-day global period affect postoperative billing?

The day-before preoperative visit and 90 days of related postoperative care are included in the global period. The surgeon's documentation should distinguish care related to the biopsy from unrelated services.

Can an assistant surgeon or co-surgeon be reported?

Medicare does not pay an assistant at surgery for this code, and co-surgeons and team surgery are not permitted.

How are multiple procedures in the same session paid?

The highest-valued procedure is paid in full; other procedures in the session are subject to the standard 50% multiple-procedure reduction.

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 45100PPRRVU2026_Oct_nonQPP.csv, line 5,463 (RVU26D)

Open CMS sourceHow we calculate rates

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