20 C.F.R. § 416.2145
We will agree under authority of section 1106 of the Act and 31 U.S.C. 6505 to provide services other than Medicaid determinations to help the State administer its Medicaid program. We will do this only if we determine it is the most efficient and economical way to accomplish the State's purpose and does not interfere with administration of the SSI program. The services can be part of a Medicaid eligibility determination agreement or a separate agreement. Under either agreement we will—