What Is InterQual? How It's Used to Deny Claims

If your insurer denied a claim for a hospital admission, a procedure, or a continuing inpatient stay, there is a good chance an algorithm played a role in that decision. That algorithm may have been InterQual—a widely used set of clinical decision-support criteria that insurers and health plans use to evaluate whether care meets medical necessity standards. Understanding what InterQual is and how it is applied gives you a foundation for challenging denials based on it.

What Is InterQual?

InterQual is a clinical criteria product developed by Change Healthcare (now part of Oracle Health). It provides evidence-based decision-support criteria that health plans, hospitals, and managed care organizations use to evaluate requests for:

• Inpatient hospital admission (acute and long-term acute)
• Continued inpatient stay (concurrent review)
• Skilled nursing facility (SNF) and rehabilitation stays
• Behavioral health and substance use treatment
• Home health services
• High-cost outpatient procedures (imaging, surgery, cardiology, oncology, and more)

InterQual criteria specify, for each type of care, the clinical indicators—vital signs, lab values, functional status, symptom severity—that must be present to support a particular level of care or service. If a patient's documented clinical picture does not meet the specified thresholds, the criteria indicate that the requested care is not supported.

How Insurers Use InterQual

Many health plans purchase InterQual's criteria and use them as the clinical standard against which Prior Authorization Denied: How to Appeal" class="auto-link">prior authorization requests and concurrent review are evaluated.

In practice, the process works like this:

1. A hospital or physician requests prior authorization or continued stay authorization.
2. The insurer's utilization management team (often a registered nurse reviewer) enters the patient's clinical data into the InterQual system.
3. The criteria determine whether the patient's presentation meets the threshold indicators.
4. If the criteria are met: approval is granted or extended.
5. If the criteria are not met: the case is escalated to a physician reviewer, who may approve or deny.

The key limitation is that InterQual criteria are designed for population-level decision support—they represent typical presentations. Individual patients may have atypical presentations, comorbidities, or clinical complexities that the criteria do not fully capture.

Why InterQual-Based Denials Happen

Documentation gaps. The patient may clinically meet InterQual criteria, but the nursing notes or physician documentation do not reflect the specific indicators the system looks for. InterQual reviewers can only evaluate what is documented.

Atypical presentations. A patient's condition may be severe but not manifest in the specific vital sign ranges or lab values that InterQual flags as critical. The treating physician may know the patient is not ready for discharge; the criteria may not reflect that.

Criteria updates. InterQual criteria are updated regularly. A criterion that applied last year may have changed, and the provider may not be aware of the current standard.

Reviewer discretion. InterQual provides a framework, but human reviewers apply it. Variation in how reviewers interpret borderline cases leads to inconsistent decisions.

Your Right to Know the Criteria Used

Under federal and state transparency requirements, you—or your physician—have the right to request the specific criteria that were applied to your denial. Ask the insurer in writing to provide:

• The specific version of InterQual criteria used
• The specific criteria applied to your case
• The clinical indicators evaluated
• The specific threshold(s) your clinical presentation did not meet

This information is essential for building an appeal. If the denial was based on documentation gaps, the treating physician can supplement the record. If the criteria themselves were misapplied, the appeal can challenge the application directly.

How to Appeal an InterQual-Based Denial

Peer-to-peer review. The most immediate tool. Your treating physician requests a direct conversation with the insurer's reviewing physician. On that call, the treating physician can present clinical nuances that the documentation alone may not convey. Many InterQual-based denials are reversed at this stage.

Supplemental documentation. If the denial was due to documentation gaps, have the treating physician addend the medical record with the specific clinical indicators that InterQual requires. Then submit the updated records with your appeal.

Challenge the criteria application. If the clinical record clearly showed criteria were met and the reviewer still denied, challenge the specific interpretation. Reference the InterQual criteria document directly in your appeal.

Expert physician letter. A letter from a board-certified specialist in the relevant field supporting the medical necessity determination carries significant weight with External Independent Review: Complete Guide" class="auto-link">external reviewers who are not bound by the insurer's InterQual-based policy.

External review. IROs) Explained" class="auto-link">Independent review organizations are not bound by InterQual. They apply their own clinical standards and the generally accepted medical community standard. Many InterQual-based denials that survive internal appeals are reversed at external review.

Fight Back With ClaimBack

ClaimBack's free AI tool drafts a professional appeal letter in minutes, tailored to your insurer and denial reason. Don't let a denial be the final word.

Fight your denial at ClaimBack →

Related Reading:

• How to Write an Insurance Appeal Letter
• What Is Medical Necessity?
• Internal vs External Insurance Appeal