42 CFR 436.1002 - FFP for services.
(b) FFP is available in expenditures for services provided to beneficiaries who were eligible for Medicaid in the month in which the medical care or services were provided, except that, for beneficiaries who establish eligibility for Medicaid by deducting incurred medical expenses from income, FFP is not available for expenses that are the beneficiary's liability.
(c) FFP is available in expenditures for services covered under the plan that are furnished -
(1) To children who are determined by a qualified entity to be presumptively eligible;
(2) During a period of presumptive eligibility;
(3) By a provider that is eligible for payment under the plan; and