Billing code 45378: ColonoscopyMedicare rate & RVUs in Illinois
Reports a diagnostic examination of the colon when the endoscopist inspects the colon without performing a separately described biopsy or therapeutic intervention.
Medicare pays $363.35–$397.87 for 45378 in the office in Illinois, from Rest Of Illinois to Chicago. 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.
On this page 9 sections
What 45378 covers
A gastroenterologist or colorectal surgeon advances a flexible endoscope through the colon to examine the bowel, commonly for evaluation of symptoms or an abnormal finding. The service can include specimen collection by brushing or washing, but it does not describe taking tissue for biopsy or treating a lesion. It is typically performed in an endoscopy unit or hospital outpatient department, with sedation commonly provided as part of the procedural setting.
Choose this code when the documented service is diagnostic inspection rather than a more specific colonoscopy procedure. The report should support the examination performed and whether a biopsy or treatment was done; when a more specific procedure is performed, report that service rather than separately reporting the diagnostic examination. CMS assigns a 0-day global period, so same-day preoperative and postoperative care is included. When multiple procedures occur in the same session, the highest-valued procedure is paid in full and other procedures are subject to the standard 50% reduction. Modifier 50 is inappropriate. Modifier 53 is separately priced. Medicare does not pay an assistant at surgery for this code, and 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 45378 pays more and less in Illinois
The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.
4 payment localities
$363.35 to $397.87
| Payment locality | Office | Facility |
|---|---|---|
| Chicago | $397.87 | $183.37 |
| East St. Louis | $371.33 | $174.97 |
| Rest Of Illinois | $363.35 | $168.48 |
| Suburban Chicago | $396.38 | $177.19 |
How the 45378 rate is calculated
Each of 45378’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 · 45378
RVUs × geographic indexes × conversion factor
Swap in your local Medicare rate.
Work 3.18Practice expense 7.73Malpractice 0.41
All indexes start at 1.000 (the national rate). Enter a ZIP or drag a slider.
Payment rules and modifiers for 45378
The CMS indicators that decide how 45378 is paid alongside other services.
CMS payment indicators · 45378
Colonoscopy
| 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 | 2 | Standard reduction: highest-valued procedure at 100%, others at 50%. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 1 | Not paid (statutory restriction). |
| 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 51 · payment effect
With and without the modifier
45378 without 51 · national office
$378.10
Colonoscopy
45378-51 · Second procedure: 50%
$189.05
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%).
45378 compared with similar codes
Compare codes
45378 vs 45380 vs 45385 vs 45330 vs 45379: national Medicare rates
Swap in your local Medicare rate.
How to choose
- 45380Colonoscopy with biopsy
- Use 45380 when tissue is sampled for biopsy. Use 45378 when the exam is diagnostic and no tissue biopsy is performed.
- 45385Snare polypectomy
- Use 45385 when a lesion is removed by snare. Diagnostic inspection alone is reported with 45378.
- 45330Flexible sigmoidoscopy
- 45330 describes diagnostic flexible sigmoidoscopy of a limited portion of the lower bowel; 45378 is for a colonoscopy.
- 45379Colonoscopy
- 45379 applies when a foreign body is removed during colonoscopy. Without that removal or another therapeutic procedure, the diagnostic service is 45378.
45378 billing questions
When should 45378 be chosen instead of 45380?
Use 45378 for diagnostic inspection without tissue biopsy. When tissue is sampled for histologic examination, report the biopsy service, 45380, instead.
Can 45378 be reported with a colonoscopy that removes a polyp?
The diagnostic inspection is part of the colonoscopy with polyp removal; report the code for the removal method rather than separately billing 45378 for the same examination.
Is modifier 50 appropriate for 45378?
No. CMS identifies bilateral adjustment as inappropriate for this code.
How should modifier 53 be handled?
CMS lists modifier 53 as separately priced for 45378. The record should support that the colonoscopy was discontinued; apply the modifier only when the circumstances meet its reporting requirements.
Does the 0-day global period include same-day care?
Yes. Same-day preoperative and postoperative care is included in the procedure's 0-day global period.
How many units are reported for the diagnostic examination?
Report one service for the colonoscopy, not a separate unit for each segment examined.
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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