MCG and InterQual: The Rulebooks Behind an Eating-Disorder Coverage Decision

What are MCG and InterQual?

MCG and InterQual are two widely used commercial criteria sets that health plans license to help decide whether a service is medically necessary. Medical-necessity criteria are the rulebooks a reviewer uses to decide whether a plan will pay for a given level of care. A plan's reviewer compares the clinical documentation a program submits against these criteria and issues an approval or a denial.

The criteria themselves are proprietary and are not public, which is part of why a denial can feel opaque. What matters for a family is not the internal wording but the role the criteria play: they are the yardstick a plan applies during prior authorization and concurrent review, and they are not the same thing as the clinical standard for what an eating disorder actually needs.

A plan does not have to use these products at all; some insurers write their own internal criteria, and some state Medicaid programs mandate a particular set. But MCG and InterQual are the two names families encounter most often, which is why a denial letter or an appeal packet may reference one of them by name. Knowing that the reference points to a licensed commercial template, rather than to a law or a universal medical rule, changes how you read it.

How a plan uses these criteria to decide a level of care

The criteria are applied to a specific question: does this person meet the plan's threshold for this level of care, right now? Eating-disorder care runs along a continuum of levels of care, from outpatient visits up through intensive outpatient, partial hospitalization, and residential or inpatient care, each defined by how much medical monitoring and structure it provides 1Ref 1National Eating Disorders Association (2024).Levels of Care for Eating Disorders.That eating-disorder care runs along a continuum of levels — outpatient, intensive outpatient, partial hospitalization, residential, and inpatient — distinguished by intensity and medical monitoring, and typically stepped up or down based on medical and psychiatric stability.. A reviewer uses MCG or InterQual to decide which rung the plan will fund.

Because the answer can change as a person stabilizes or destabilizes, the criteria are re-applied at each concurrent review. Level-of-care decisions, whether stepping up or stepping down, are driven by clinical progress and stability, and transitions between levels are clinically consequential 2Ref 2Frontiers in Psychology (peer-reviewed study) (2021).Predictors of Stepping Up to Higher Level of Care Among Eating Disorder Patients in a Partial Hospitalization Program.That level-of-care decisions to step up or down are driven by clinical progress and stability, and that transitions between levels are clinically consequential.. The criteria are the plan's attempt to encode that judgment into a checklist.

Where the rulebook and the clinical standard can diverge

A commercial criteria set is not the professional standard of care, and the two can point in different directions. The current US professional guideline recommends eating-disorder-focused psychotherapy, recommends family-based treatment for adolescents with anorexia or bulimia, and calls for an initial evaluation that includes a medical assessment 3Ref 3Crone C, Fochtmann LJ, Attia E, et al. (American Psychiatric Association) (2023).The American Psychiatric Association Practice Guideline for the Treatment of Patients With Eating Disorders (Fourth Edition).That evidence-based care recommends eating-disorder-focused psychotherapy, recommends family-based treatment for adolescents with anorexia or bulimia, and calls for an initial evaluation that includes a medical assessment.. A plain-language summary of that guideline underscores that comprehensive evaluation and evidence-based psychotherapy are the recommended core of care 4Ref 4Arnold MJ (2024).Treating Patients With Eating Disorders: Guidelines From the American Psychiatric Association.A plain-language summary of the APA guideline confirming that comprehensive evaluation, eating-disorder-focused psychotherapy, and family-based therapy for adolescents are recommended..

When a proprietary criteria set would deny care that the clinical guideline supports, the gap between them is the substance of an appeal. A treating clinician's assessment of the person in front of them is the clinical case; the criteria are a general template. A denial is a decision about the template, not a verdict on the person.

The parity right that sits above the criteria

Whatever criteria a plan uses, it cannot apply them more harshly to mental-health care than to comparable medical care. Under the Mental Health Parity and Addiction Equity Act, plans that cover mental-health and substance-use benefits must generally apply financial requirements and treatment limitations no more restrictively than they do for medical and surgical benefits 5Ref 5Centers for Medicare & Medicaid Services (2024).The Mental Health Parity and Addiction Equity Act (MHPAEA).That MHPAEA generally requires plans covering mental-health benefits to apply financial requirements and treatment limitations no more restrictively than for comparable medical and surgical benefits..

That parity right is why the criteria themselves can be challenged, not just their application to one case. If a plan reviews eating-disorder admissions against a tougher standard than it uses for a comparable physical-health admission, that difference is a parity problem. A family does not have to argue this alone; the treating program and outside navigators do it routinely.

What you can ask to see and do

You can ask a plan which criteria set it used and request the specific reason for a denial in writing, and you can ask your program to walk you through how the clinical record maps to the requested level of care. Good questions to ask treatment providers include how they document medical necessity and how they handle authorization and appeals 6Ref 6National Eating Disorders Association (2024).Questions to Ask Eating Disorder Treatment Providers.That carers and patients should ask practical questions of a program, including how it documents care and handles authorization and aftercare..

• Ask the plan to name the criteria it applied and to state the denial reason in writing.
• Ask the program how its notes support the requested level of care.
• Keep dated copies of every letter, because appeal windows are short.

Understanding a level of care decision framework and how residential admission criteria differ from PHP admission criteria helps you see whether a denial reflects the clinical picture or only the template.

The criteria are not the last word

A denial based on MCG or InterQual is a first answer, not a final one. Because the criteria are a general template applied by a reviewer who has not met the patient, they are frequently overturned when the full clinical case is presented on appeal. The treating clinician's judgment, the professional guideline, and the parity right are all grounds a program can raise.

A coverage denial does not mean the care is unnecessary; it means one reviewer applied one rulebook to a summary. Choosing a level of care is ultimately a clinical decision made with the treating team. The insurer's criteria decide what the plan will pay for, and that decision can be contested through the appeal process.

This distinction is worth holding onto in a hard moment. A family reading the words does not meet criteria can hear it as a judgment that their loved one is not really unwell, when it is only a statement that a summary did not line up with a template on a given day. The treating team sees the whole person; the reviewer sees a document. Naming that difference plainly is often the first step in a successful appeal.