CPT code 43645: Gastric bypass, small-intestine reconstruction2026 Medicare rate & RVUs

Medicare pays $1,718.14 for 43645 nationally in a facility.

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

What 43645 covers

A bariatric surgeon performs this laparoscopically to create a gastric bypass and reconstruct the small intestine in a way intended to limit nutrient absorption. It represents a more extensive intestinal reconstruction than a standard laparoscopic Roux-en-Y gastric bypass. The operation is typically performed in a hospital or other surgical facility for treatment of severe obesity; the operative report should identify the bypass and intestinal reconstruction performed.

Select this code when the documented laparoscopic operation includes both gastric bypass and the small-intestine reconstruction to limit absorption. A standard Roux-en-Y bypass without that reconstruction is reported with 43644. CMS assigns a 90-day global period, including the day-before preoperative visit and 90 days of related postoperative care. When multiple procedures are performed in the same session, the highest-valued procedure is paid in full and the others are subject to the standard 50% multiple-procedure reduction. Assistant-at-surgery services may be paid; co-surgeon payment requires supporting documentation, and team-surgery payment is 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 43645 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

43645 rates by state

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

How the 43645 rate is calculated

Each of 43645’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.

Payment rules and modifiers for 43645

43645 has a 90-day global period: related visits in that window are included in the surgery payment.

What modifiers do to the payment

When to use modifier 51

43645 compared with similar codes

How to choose

43644Gastric bypassRoux-en-Y, laparoscopic

43644 describes laparoscopic Roux-en-Y gastric bypass. Choose 43645 when the operation also reconstructs the small intestine to limit absorption.

43847Bariatric surgerySmall-intestine reconstruction

Both describe gastric bypass with intestinal reconstruction to limit absorption, but 43847 is the open approach; 43645 is laparoscopic.

43659Laparoscopic stomach procedureUnlisted procedure

43659 is an unlisted laparoscopic stomach procedure. Use 43645 when the documented bypass and intestinal reconstruction match its defined service.

Codes related to 43645

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

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

Open CMS sourceHow we calculate rates