Carriers are required to update the rates for portable X-ray transportation allowances on an annual basis using independently determined measures of the cost of providing this service. A number of readily measured indicators (e.g., ambulance inflation factor, the Medicare economic index) that are used by the Medicare program to adjust payment rates for other types of services may be appropriate to use to update the rate for years that the carrier does not re-evaluate the payment. Each carrier has the flexibility to identify the index it will use to update this rate. In addition, the carrier can consider locally identified factors that are measured independently of the Centers for Medicare & Medicaid Services (CMS) as an adjunct to the annual adjustment. First Coast Service Options, Inc. utilized the ambulance inflation factor of 2.7 percent as outlined in the CMS change request 5801, transmittal 1375 dated November 9, 2007, in determining the payment limit on claims for portable X-ray transportation services with dates of service on or after January 1, 2008.