CPT code 81599: Unlisted MAAA, unlisted assay2026 Medicare rate & RVUs

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

What 81599 covers

CPT 81599 is used for a multianalyte assay with algorithmic analysis when no more specific CPT code describes the assay performed. The laboratory combines results from multiple analytes through an algorithm to produce an interpreted result, such as a risk score or classification. A laboratory reports this code for the assay as a whole; it does not identify a particular disease, specimen, analyte set, or algorithm. Compare the assay's actual method and intended result with available assay-specific codes before selecting 81599.

Medicare assigns status X: the service is not a physician service under the Medicare statute, so the physician fee schedule never pays it. When covered, Medicare pays it under another fee schedule or payment system. Records should identify the assay performed, its analytes and algorithmic interpretation, and its clinical purpose to support code selection.

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 81599 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

81599 rates by state

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

How the 81599 rate is calculated

Each of 81599’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 81599

81599 has no global surgery period, no multiple-procedure, bilateral or assistant-at-surgery adjustment, and no professional/technical split. What changes the payment is where the service happens: the place of service on the claim decides whether Medicare pays the office or the facility rate.

81599 compared with similar codes

How to choose

81519Breast gene assay21-gene recurrence score

81519 identifies a specific breast cancer multianalyte assay. Use 81599 only when no more specific code describes the assay performed.

81525Colon tumor profileTwelve-gene recurrence score

81525 identifies a specific colon cancer multianalyte assay. It is not a general code for other algorithmically interpreted tests.

81528Stool DNA testDNA markers and hemoglobin

81528 identifies a colorectal cancer screening assay. 81599 is for a multianalyte assay with algorithmic analysis that lacks a more specific CPT code.

Codes related to 81599

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