42 CFR § 435.910 - Use of social security number.
(a) Except as provided in paragraph (h) of this section, the agency must require, as a condition of eligibility, that each individual (including children) seeking Medicaid furnish each of his or her Social Security numbers (SSN).
(f) The agency must not deny or delay services to an otherwise eligible individual pending issuance or verification of the individual's SSN by SSA or if the individual meets one of the exceptions in paragraph (h) of this section.
(g) The agency must verify the SSN furnished by an applicant or beneficiary with SSA to ensure the SSN was issued to that individual, and to determine whether any other SSNs were issued to that individual.
(i) Is not eligible to receive an SSN;
(ii) Does not have an SSN and may only be issued an SSN for a valid non-work reason in accordance with 20 CFR 422.104; or
(iii) Refuses to obtain an SSN because of well-established religious objections.
(2) The identification number may be either an SSN obtained by the State on the applicant's behalf or another unique identifier.
(3) The term well established religious objections means that the applicant -
(i) Is a member of a recognized religious sect or division of the sect; and
(ii) Adheres to the tenets or teachings of the sect or division of the sect and for that reason is conscientiously opposed to applying for or using a national identification number.