The following practitioners who provide services under the Medicare program are required to accept assignment for all Medicare claims for their services. This means that they must accept the Medicare allowed amount as payment in full for their practitioner services. The beneficiary’s liability is limited to any applicable deductible plus the 20 percent coinsurance.

Assignment is mandated for the following claims:

• Clinical diagnostic laboratory services and physician lab services;

• Physician services to individuals dually entitled to Medicare and Medicaid;
Services of physician assistants, nurse practitioners, clinical nurse specialists, nurse midwives, certified registered nurse anesthetists, clinical psychologists, clinical social workers, registered dietitians/nutritionists, anesthesiologist assistants, and mass immunization roster billers.

NOTE: The provider type Mass Immunization Roster Biller can only bill for influenza and pneumococcal vaccinations and administrations. These services are not subject to the deductible or the 20 percent coinsurance.

• Ambulatory surgical center services; (No deductible and 25% coinsurance for colorectal cancer screening colonoscopies {G0105 and G0121) and effective for dates of service on or after January 1, 2008 G0104 also applies);
• Home dialysis supplies and equipment paid under Method II for dates of service prior to January 1, 2011.  Refer to Section 30.3.8 for information regarding the elimination of Method II home dialysis for dates of service on and after January 1, 2011;

• Drugs and biologicals; and,  

• Ambulance services

When these claims are inadvertently submitted as unassigned, carriers process them as assigned.
Note that, unlike physicians, practitioners, or suppliers bound by a participation agreement, practitioners/entities providing the services/supplies identified above are required to accept assignment only with respect to these services/supplies (unless they have signed participation agreements which blanket the full range of their services).  

The carrier system must be able to identify (and update) the codes for those services subject to the assignment mandate.  
For the practitioner services of physicians and independently practicing physical and occupational therapists, the acceptance of assignment is not mandatory. Nor is the acceptance of assignment mandatory for the suppliers of radiology services or diagnostic tests. However, these practitioners and suppliers may nevertheless voluntarily agree to participate to take advantage of the higher payment rate, in which case the participation status makes assignment mandatory for the term of the agreement. Such an agreement is known as the Medicare Participating Physician or Supplier Agreement. (See § Carrier Participation Agreement.) Physicians, practitioners, and suppliers who sign this agreement to participate are agreeing to accept assignment on all Medicare claims. The Medicare Participation Agreement and general instructions are on the CMS Web site.

Future updates to this section will be communicated in a Recurring Update Notification.