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Helping patients get the right care

You want to recommend the best treatment option for your patients. There are several tools that can help.

For patients with commercial plans, Aetna® will use the Level of Care Utilization System (LOCUS) and the Child and Adolescent Level of Care Utilization System/Child and Adolescent Service Intensity Instrument (CALOCUS/CASII) for its medical necessity reviews.* 


This person-centered approach aims to find the best fit between individual needs and behavioral health services. 


Patients with Medicare Advantage plans: continue to use CMS criteria for all Organizational Determinations. LOCUS will be used in all other cases. 


These materials may not be duplicated without expressed written permission from the American Association for Community Psychiatry. 


LOCUS© Evaluation Parameters (PDF) 

LOCUS© Levels of Care Descriptions (PDF) 

LOCUS© Guides for Patients and Families (PDF)

CALOCUS/CASII® Levels of Care Descriptions (PDF)





*This replaces the use of the Level of Care Assessment Tool (LOCAT) for behavioral health reviews. 


For more information about LOCUS, visit the American Association of Community Psychiatrists website.  


For more information about the CALOCUS/CASII, visit the Academy of Child and Adolescent Psychiatry website. 

This guide is used by clinicians to decide appropriate levels and types of services that are medically necessary for a patient. It can also help you with the coverage determination process.


ABA medical necessity guide (PDF)

The American Society of Addiction Medicine (ASAM) has a new edition of its criteria. Addiction specialists use these criteria to help them choose treatment options. The criteria also help patients and their families better understand treatment options.


Copyright 2015 by the American Society of Addiction Medicine.  Reprinted with permission.  No third party may copy this document in whole or in part in any format or medium without the prior written consent of ASAM.


Introduction to the ASAM criteria for members (PDF)

Behavioral health providers: reinstating Custodial Care decision reason effective immediately


In June 2021, we replaced the Level of Care Assessment Tool (LOCAT) medical necessity criteria with the Level of Care Utilization System (LOCUS) and the Child and Adolescent Level of Care Utilization System/Child and Adolescent Service Intensity Instrument (CALOCUS/CASII) and suspended the use of the Custodial Care decision reason.


What’s changing


Effective immediately Aetna/CVS Health® will resume using a Custodial Care decision reason.


The new custodial care decision reason is as follows:


“When care is deemed to fall under custodial care, the care is no longer eligible for coverage. Based on the information provided the Member has reached the maximum achievable level of mental function with the current treatment at the current level of care; and/or the services are given mainly to maintain, rather than improve, a level of mental function, and/or provide a surrounding free from environmental conditions that can worsen the person’s physical or mental state.”


Why is the Custodial Care decision reason changing?


We’ve revised the custodial care policy in consideration of behavioral health clinical situations.


What else to know


The utilization management (UM) process has not changed. You can continue to use the same process that you do today.


The member's benefit plan governs coverage and the conclusion that a particular service or supply is medically necessary does not constitute a representation or warranty that a service or supply is covered.

Legal notices

Aetna is the brand name used for products and services provided by one or more of the Aetna group of companies, including Aetna Life Insurance Company and its affiliates (Aetna).

Health benefits and health insurance plans contain exclusions and limitations.

See all legal notices

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