CPT code 31599: Unlisted larynx procedure2026 Medicare rate & RVUs in California

CMS doesn’t publish an office rate for 31599 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 31599 covers

31599 is the unlisted CPT code for a procedure on the larynx that has no specific listed code describing the work. Otolaryngologists may report it when the procedure is not represented by a defined laryngeal service; it is not a substitute for a listed code that accurately describes what was performed. Diagnostic laryngoscopy, laryngoscopy with biopsy, laryngoscopic lesion removal, and laryngeal medialization each have specific codes when those services are performed.

Medicare assigns physician fee schedule status C (carrier priced): CMS publishes no national payment, and the Medicare Administrative Contractor sets payment for each claim. The contractor sets the global period. For multiple procedures performed in the same session, the standard multiple procedure reduction pays the highest-valued procedure in full and the other procedures at 50%.

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 31599 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 31599 rate is calculated

Each of 31599’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 31599

The CMS indicators that decide how 31599 is paid alongside other services.

What modifiers do to the payment

When to use modifier 51

31599 compared with similar codes

How to choose

31575LaryngoscopyFlexible, diagnostic

31575 describes diagnostic laryngoscopy. Use 31599 only when the laryngeal service performed is not accurately represented by a specific listed code.

31576Laryngeal biopsyFlexible endoscopic approach

31576 describes laryngoscopy with biopsy. It applies when that is the service performed, rather than an unlisted laryngeal procedure.

31578LaryngoscopyFlexible scope, lesion removal

31578 describes laryngoscopic removal of a lesion. Use 31599 for a distinct laryngeal procedure not captured by that listed service.

31591LaryngoplastyUnilateral medialization

31591 describes laryngeal medialization. Choose 31599 only when the actual procedure is not represented by that code or another specific listing.

Codes related to 31599

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