CPT code 25100: Wrist biopsy, open joint approach2026 Medicare rate & RVUs in California

CMS doesn’t publish an office rate for 25100 in California.

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

What 25100 covers

The surgeon opens the wrist joint and removes a tissue sample for diagnostic evaluation. The specimen may be synovium or other intra-articular tissue submitted for pathologic or microbiologic study when the cause of persistent synovitis, suspected infection, or another joint abnormality remains uncertain. Orthopedic and hand surgeons typically perform this procedure in a hospital operating room or ambulatory surgery center; it is an open surgical biopsy, not needle aspiration or arthroscopic sampling.

Report the code when the operative record supports an open joint approach and tissue was obtained for biopsy. Document the wrist, operative approach, sampled tissue, and diagnostic purpose. CMS assigns a 90-day global period, including the day-before preoperative visit and 90 days of related postoperative care. For multiple procedures in one session, the highest-valued procedure is paid in full and others at 50%. Bilateral reporting with modifier 50 is paid at 150%. Assistant-at-surgery payment requires documented medical necessity; 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 25100 pays more and less in California

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

29 of 29 payment localities

How the 25100 rate is calculated

Each of 25100’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 25100

25100 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 50

25100 compared with similar codes

How to choose

25101Wrist arthrotomyExploration, drainage, or foreign body

25100 identifies an open wrist-joint procedure to obtain a diagnostic tissue specimen. 25101 is used when the operative objective is exploration or treatment.

29840Wrist arthroscopyDiagnostic examination

29840 is a diagnostic arthroscopic wrist procedure, with or without synovial biopsy. Choose 25100 when the biopsy is performed through an open arthrotomy.

20605Joint procedureIntermediate joint, no ultrasound

20605 describes aspiration or injection of an intermediate joint such as the wrist. It involves joint fluid, not an open surgical tissue biopsy.

Codes related to 25100

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