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LOCUS, CALOCUS-CASII, ECSII - Guidance on Clinical Criteria Decisions in the Treatment of Mental Health Conditions

Optum currently uses the Level of Care Utilization System (LOCUS), the Child and Adolescent Service Intensity Instrument (CASII) and the Early Childhood Service Intensity Instrument (ECSII) for guidance on clinical criteria decisions for the treatment of behavioral health conditions across most Commercial and Medicaid membership. 

NEW Change Effective 11/13/2021:    The American Academy of Child and Adolescent Psychiatry (AACAP) and the American Association for Community Psychiatry (AACP) have announced that the Child and Adolescent Level of Care Utilization System (CALOCUS) and the Child and Adolescent Service Intensity Instrument (CASII) have been unified into a single instrument, the Child and Adolescent Level of Care/Service Intensity Utilization System (CALOCUS-CASII) for ages 6-18.

Effective 11/13/2021, Optum will replace CASII with the merged CALOCUS-CASII assessment instrument for ages 6-18. The use of LOCUS and ECSII are not impacted by this change.

  • Level of Care Utilization System (LOCUS) – a standardized level of care assessment tool developed by the American Association of Community Psychiatrists used to make clinical determinations and placement decisions for adults.
  • Child and Adolescent Level of Care Utilization System and Child and Adolescent Service Intensity Instrument (CALOCUS-CASII) – a standardized assessment tool developed by the American Academy of Child and Adolescent Psychiatry (AACAP) and the American Association for Community Psychiatry (AACP) used to make clinical determinations and to provide level of service intensity for children and adolescents ages 6-18.
  • Early Childhood Service Intensity Instrument (ECSII) – a standardized assessment tool developed by the AACAP used to make clinical determinations and to provide level of service intensity for children ages 0-5.

Optum uses these externally developed guidelines for a number of reasons:

  • Externally validated: LOCUS, CALOCUS-CASII and ECSII criteria were created and updated based on the changing landscape of evidence informed care, market and regulatory considerations, and feedback from stakeholders across the care system.
  • Common language drives improved care: The use of these guidelines creates a common language for providers with payers, regulators, and other stakeholders of the care system, which results in a clearer understanding of patient needs. The six dimensions provide a more holistic view of acuity and chronicity of behavioral condition, thereby promoting more appropriate care for patients and a better overall experience.
  • Effective management of behavioral health services: Three main concepts need to be considered and balanced in effectively managing behavioral health services:  (1) Use of wrap-around services; (2) tailored to specific age of the member; and, (3) adopts a system of care approach. The LOCUS, CALOCUS-CASII and ECSII criteria best meet all three of these concepts. 

Please note, we will continue to use The ASAM Criteria, developed by the American Society of Addiction Medicine, as the clinical criteria for substance use disorder services.

LOCUS, CALOCUS-CASII and ECSII are now effective in all states unless superseding state, federal, contractual or customer requirements apply unless superseding state, federal, contractual or customer requirements apply. Note that some markets and programs are already using these guidelines.

LOCUS clinical assessment information can be found on the Guidelines/Policies & Manuals page. We are unable to provide AACAP and AACP copyrighted materials for CALOCUS-CASII and ECSII; however, links to optional training information offered through AACAP can be found on the right side of this page.

Frequently Asked Questions (rev. 11/2021)

Educational Resources

Below are links to current training resources provided by Deerfield Solutions and the American Academy of Child and Adolescent Psychiatry.  For more information, visit these websites: