45 CFR § 302.31 - Establishing paternity and securing support.
The State plan shall provide that:
(a) The IV-D agency will undertake:
(2) In the case of any individual with respect to whom an assignment as defined in § 301.1 of this chapter is effective, to secure support for a child or children from any person who is legally liable for such support, using State laws regarding intrastate and interstate establishment and enforcement of support obligations. Effective October 1, 1985, this includes securing support for a spouse or former spouse who is living with the child or children, but only if a support obligation has been established for that spouse and the child support obligation is being enforced under the title IV-D State plan.
(3) When assigned medical support payments are received and retained by a non-IV-A Medicaid recipient, the IV-D agency shall notify the Medicaid agency whenever it discovers that directly received medical support payments are being, or have been, retained.
(b) Upon receiving notice of a claim of good cause for failure to cooperate, the IV-D agency will suspend all activities to establish paternity or secure support until notified of a final determination by the appropriate agency.
(c) The IV-D agency will not undertake to establish paternity or secure support in any case for which it has received notice that there has been a finding of good cause unless there has been a determination that support enforcement may proceed without the participation of the caretaker or other relative. If there has been such a determination, the IV-D agency will undertake to establish paternity or secure support but may not involve the caretaker or other relative in such undertaking.