20 CFR § 30.707 - How are payments to providers calculated?
Payment for a procedure, service or device identified by a HCPCS/CPT code shall not exceed the amount derived by multiplying the RVU values for that procedure by the GPCI values for services in that area and by the conversion factor to arrive at a dollar amount assigned to one unit in that category of service.
(a) The “locality” which serves as a basis for the determination of cost is defined by the Bureau of Census Metropolitan Statistical Areas. OWCP shall base the determination of the relative per capita cost of medical care in a locality using information about enrollment and medical cost per county, provided by CMS.
(b) OWCP shall assign the RVUs published by CMS to all services for which CMS has made assignments, using the most recent revision. Where there are no RVUs assigned to a procedure, OWCP may develop and assign any RVUs it considers appropriate. The geographic adjustment factor shall be that designated by GPCI values for Metropolitan Statistical Areas as devised for CMS and as updated or revised by CMS from time to time. OWCP will devise conversion factors for each category of service as appropriate using OWCP's processing experience and internal data.
(c) For example, if the RVUs for a particular surgical procedure are 2.48 for physician's work (W), 3.63 for practice expense (PE), and 0.48 for malpractice insurance (M), and the conversion factor assigned to one unit in that category of service (surgery) is $61.20, then the maximum allowable charge for one performance of that procedure is the product of the three RVUs times the corresponding GPCI values for the locality times the conversion factor. If the GPCI values for the locality are 0.988(W), 0.948 (PE), and 1.174 (M), then the maximum payment calculation is: