Section 424.521 - Request for payment by certain provider and supplier types(a)Request for payment by certain provider and supplier types.(1) The providers and suppliers identified in paragraph (a)(2) of this section may retrospectively bill for services when the provider or supplier has met all program requirements (including State licensure requirements), and services were provided at the enrolled practice location for up to- (i) Thirty days prior to their effective date if circumstances precluded enrollment in advance of providing services to Medicare beneficiaries; or(ii) Ninety days prior to their effective date if a Presidentially-declared disaster under the Robert T. Stafford Disaster Relief and Emergency Assistance Act, 42 U.S.C. 5121-5206 (Stafford Act) precluded enrollment in advance of providing services to Medicare beneficiaries.(2) The provider and supplier types to which paragraph (a)(1) of this section applies are as follows: (ii) Non-physician practitioners.(iii) Physician organizations.(iv) Non-physician practitioner organizations.(vi) Opioid treatment programs.(vii) Part B hospital departments.(viii) Clinical Laboratory Improvement Amendment labs.(ix) Intensive cardiac rehabilitation facilities.(xi) Mass immunizers/pharmacies.(xii) Radiation therapy centers.(xiii) Home infusion therapy suppliers.(xiv) Physical therapists.(xv) Occupational therapists.(xvi) Speech language pathologists.79 FR 72531, Dec. 5, 2014, as amended at 84 FR 63203, Nov. 15, 2019; 85 FR 70355, Nov. 4, 2020; 86 FR 62419, Nov. 9, 2021 84 FR 63203, 1/1/2020; 85 FR 70355, 1/1/2021; 86 FR 62240, 1/1/2022