N.M. Admin. Code § 8.321.2.24
IMD is defined as any facility with more than 16 beds that is primarily engaged in the delivery of psychiatric care or treating substance use disorders (SUD) that is not part of a certified general acute care hospital. The federal medicaid IMD exclusion generally prohibits payment to these providers for recipients aged 22 through 64. Based upon a New Mexico state plan amendment and 1115 waiver MAD covers inpatient hospitalization in an IMD for SUD diagnoses only with criteria for medical necessity and based on ASAM admission criteria. The coverage may also include co-occurring behavioral health disorders with the primary SUD. For other approved IMD stays for eligible recipients under age 21 or over age 64, the number of days is determined by medical necessity as the age restriction for IMDs does not apply to ages under 21 or over 65. Also refer to 8.321.2.23 NMAC, Inpatient Psychiatric Care in Freestanding Psychiatric Hospitals and Psychiatric Units of Acute Care Hospitals.
N.M. Admin. Code § 8.321.2.24