InterQual Criteria

What is InterQual Criteria?

InterQual Criteria are evidence-based clinical decision support tools consisting of measurable clinical indicators and diagnostic services used to evaluate medical necessity and determine appropriate levels of care for patients. These criteria function as structured rule sets that healthcare payers and providers apply to assess whether proposed medical services are clinically indicated and delivered at the suitable care level.

The framework relies on the Intensity Severity Discharge (ISD) approach, which organizes clinical content into 14 body systems. Each body system contains three distinct criteria sets:

• Intensity of Service: Measures the level of medical intervention required

• Severity of Illness: Evaluates the patient’s clinical condition and complications

• Discharge Screens: Assesses readiness for transition or discharge

InterQual examines patient-specific factors including severity of illness, comorbidities, and complications rather than relying solely on diagnosis. This methodology allows the criteria to apply across acute hospital care settings regardless of facility location or size. The clinical indicators provide objective endpoints for service, enabling reviewers to perform assessments with built-in checkpoints that identify patient progress, plateau, or goal achievement.

Healthcare organizations employ these criteria as first-level screening tools during utilization review processes. When authorization or prior approval requests are received, utilization review nurses compare submitted documentation against the specific criteria thresholds. Cases meeting the established criteria receive approval, while those falling short undergo physician review. The criteria serve supplementary functions and cannot independently deny cases, as only physicians retain authority to determine clinical appropriateness.

The clinical development team performs systematic reviews and critical appraisals of medical evidence using elements of the GRADE approach. A clinical review panel comprising more than 1,200 independent, multidisciplinary experts provides extensive peer review to ensure the criteria reflect current standards of care and best practices ^[1]. This evidence-based foundation draws from clinical data, medical literature, and best practice guidelines ^[2][3].

InterQual undergoes continuous updates with annual releases to align with evolving healthcare standards. More than 4,500 healthcare organizations worldwide utilize these criteria to support appropriate clinical decisions, reduce administrative burden, and manage utilization effectively ^[1]. The portfolio spans the continuum of medical and behavioral health care, offering comprehensive content for various care settings and patient populations.

Why is InterQual Criteria important?

Healthcare organizations require standardized approaches to medical necessity determination due to variations in clinical decision-making and utilization management practices. InterQual provides objective, consistent criteria that guide defensible decisions ensuring appropriate quality care across diverse provider settings. This standardization addresses a fundamental challenge in healthcare delivery where subjective assessments can lead to inconsistent patient classification and resource allocation.

The criteria support evidence-based clinical decisions by incorporating systematic reviews of medical literature and critical appraisals conducted by multidisciplinary experts. Over 1,100 independent physicians and clinicians contribute to peer review validation, ensuring alignment with current standards of care and best practices ^[4]. This rigorous development process enables healthcare organizations to reduce administrative burden, enhance payer-provider relations, and improve care quality ^[4]. The framework allows utilization review nurses to perform first-level screening by comparing documentation against specific criteria thresholds, streamlining approval workflows for cases meeting established standards ^[3].

Hospital case management relies heavily on these criteria to differentiate between observation and inpatient status classifications. This distinction carries significant financial implications, as a hypothetical three-day syncope hospitalization generates approximately $4,000 in revenue when billed as inpatient versus only $1,500 for observation status ^[3]. With nearly 460,000 syncope hospitalizations occurring annually, this represents millions in potential payment differences ^[3]. Recovery Audit Contractors historically use InterQual during reviews, prompting hospitals to align hospitalization status with audit expectations ^[3]. Patients with higher severity of illness, increasing comorbidities, and requiring more intensive treatment typically meet inpatient status criteria ^[3].

InterQual addresses critical access gaps in behavioral health care, where only 41% of individuals meeting criteria for certain disorders receive treatment ^[4]. The standardized guidelines facilitate consistent care decisions, improving likelihood of timely, appropriate interventions that enhance health outcomes. The criteria consider severity of illness, additional medical conditions, and care location to determine the safest and most appropriate services ^[3]. When criteria are met, cases receive approval; unmet criteria trigger referral to medical directors, maintaining that only physicians determine lack of clinical appropriateness ^[3].

How does InterQual Criteria work?

The review process begins with selecting the appropriate criteria subset based on the patient’s clinical situation and care setting. Reviewers access InterQual through various delivery platforms including browser-based systems, provider portals, or locally installed applications ^[5]. The criteria present in either decision-tree format or question-and-answer format depending on the product selected ^[6].

Clinical assessment

Utilization review nurses collect required information including patient demographics, medical history, clinical notes, photographs, and relevant medical record elements before initiating the review ^[7]. The assessment evaluates specific clinical indicators against established thresholds within the criteria framework. Patients with higher severity of illness, increasing comorbidities, and requiring more intensive treatment often meet inpatient status criteria ^[1]. The branching logic examines findings from diagnostic tests, symptoms, and clinical presentations to determine appropriate care levels ^[1].

Guideline selection

Reviewers select the applicable subset from the criteria library, then choose specific parameters based on care type. For Level of Care acute adult and pediatric cases, an Episode Day is selected from the list ^[8]. Long Term Acute Care and Inpatient Rehabilitation require selecting a review type: Preadmission, Admission, Continued Stay, or Discharge ^[8]. Subacute and Skilled Nursing reviews involve choosing from Preadmission, Admission, Week 1, Continued Stay, Week 2-4, or Discharge Screens ^[8]. InterQual behavioral health criteria require selecting a level of care followed by the appropriate Episode Day or Week ^[8].

Documentation review

The decision tree expands through click-based navigation, allowing reviewers to view criteria sections by clicking plus signs or using the Expand All function ^[8]. Six distinct note types provide contextual information: Informational Notes offer clinical practice reminders and literature references, Quality Indicator Notes flag conditions with existing quality data, Transition Plan Notes identify readmission risks, mandatory Red Notes contain required reading, Care Management Notes guide quality care progression, and CMS Two-Midnight Rule Notes provide regulatory instructions ^[8].

Decision process

Question-and-answer format products display sequential questions requiring single or multiple answers ^[6]. Reviewers progress through queries by selecting responses, with the system automatically advancing for single-answer questions ^[6]. Upon completion, the system generates recommendations displaying results that vary by product, ranging from not recommended to multiple recommendations ^[6]. The final determination provides ICD, CPT, and HCPCS codes applicable to the review ^[6].

Types of InterQual Criteria modules

The InterQual portfolio organizes specialized modules into four primary content suites delivering clinical decision support across medical and behavioral health continuums. Each suite contains multiple modules addressing specific patient populations, care settings, and clinical scenarios.

Level of Care modules

Level of Care modules enable prospective, concurrent, and retrospective clinical appropriateness assessments by evaluating severity of illness, comorbidities, complications, and service intensity. The Acute Adult module evaluates admission, continued stay, and discharge appropriateness for patients aged 18 and older, presenting condition-specific criteria with complications, comorbidities, guideline treatments, and length-of-stay benchmarks in single-view format ^[4]. The Acute Pediatric module applies identical condition-specific formatting for patients under 18 years ^[4].

The Long-Term Acute Care module incorporates responder and partial responder criteria enabling clinicians to adjust timeframes and interventions based on patient outcomes ^[4]. The Inpatient Rehabilitation module addresses admission and discharge decisions for adult and pediatric populations, including methods for managing complications from medical instability ^[4]. The Subacute and Skilled Nursing module identifies medical necessity and appropriate care complexity based on clinical need and stability ^[4]. The Home Care module determines appropriateness of initial reviews, ongoing service needs, visit recommendations, and discharge for adult and pediatric patients requiring intermittent skilled home care, private-duty nursing, hospice, and palliative care ^[4]. The Outpatient Rehabilitation and Chiropractic module addresses rehabilitation and chiropractic care authorization, ongoing needs, and transition planning ^[4].

Behavioral Health modules

InterQual behavioral health criteria employ continuum format presenting all care settings in single view with episode-day and episode-week features providing timeline guidance. The Adult and Geriatric Psychiatry module supports initial and continued-stay decisions for patients aged 18 and older, considering symptoms, functional status, support systems, and safety ^[4]. The Child and Adolescent Psychiatry module addresses patients aged 4 through 17 years ^[9], ^[4]. The Substance Use Disorders module guides appropriate care planning for patients aged 12 and older ^[4]. The Behavioral Health Services module supports medical necessity determinations for procedures including applied behavioral analysis, psychological testing, electroconvulsive therapy, neuropsychological testing, and vagus nerve stimulation ^[4].

Ambulatory Care Planning modules

Ambulatory Care Planning modules feature extensive informational notes, references, and question-and-answer format supporting efficient workflows. The Procedures module covers more than 460 high-volume, high-cost procedures across major body systems for adults and children ^[4]. The Imaging module encompasses more than 200 unique imaging tests organized into more than 30 test families ^[4]. The Durable Medical Equipment module addresses medical necessity documentation for nearly 400 equipment pieces and accessories ^[4]. The Molecular Diagnostics module provides criteria covering more than 750 molecular and genetic diagnostic tests organized into more than 120 test families ^[4]. The Specialty Rx Oncology module guides appropriate oncology drug use for on-label and off-label indications, incorporating National Comprehensive Cancer Network recommendations ^[4]. The Specialty Rx Non-Oncology module addresses more than 140 drugs for common conditions with step therapy guidance ^[4]. The Specialty Referral module covers more than 160 conditions with specialist consultation criteria ^[4]. The Retrospective Monitoring module supports retrospective assessments of more than 260 surgical and nonsurgical invasive procedures ^[4].

Medicare Criteria modules

The Medicare Criteria suite provides content aligned with Medicare National and Local Coverage Determinations and policy articles, presented in question-and-answer format. The suite includes Medicare Post-Acute and Durable Medical Equipment, Medicare Procedures, Medicare Imaging, Medicare Molecular Diagnostics and Lab, Medicare Pharmacy, and Medicare Behavioral Health ^[10].

Specialty modules

Specialty modules address complex care management, specialty pharmacy applications, and care coordination needs beyond primary suite coverage ^[11].

InterQual Criteria vs MCG criteria

Both InterQual and MCG (Milliman Care Guidelines) originated in the late 1970s and 1980s to establish standardized guidelines for appropriate hospital admissions ^[3]. These evidence-based, peer-reviewed tools serve identical functions in medical necessity review for inpatient and outpatient services ^[12]. Healthcare payers and providers apply both systems during utilization review processes, though payer preferences differ substantially.

Commercial insurance plans and Medicare Advantage programs predominantly rely on MCG, whereas Medicaid programs typically implement InterQual ^[13]. Traditional Medicare uses the 2-midnight rule rather than either commercial product, though Quality Improvement Organizations employ InterQual for first-level reviews of short inpatient stays ^[13]. This multiplicity of approaches creates complexity for utilization review screening across different payer types.

InterQual criteria demonstrate stricter standards in certain respects, incorporating more precise clinical benchmarks for each care level ^[14]. This heightened specificity can result in increased denials for borderline cases involving inpatient versus observation status or discharge versus continued stay decisions ^[14]. Conversely, MCG is characterized as more simplistic and user-friendly, while InterQual provides more thorough clinical assessments ^[3].

Both systems require licensing agreements granting access to proprietary criteria through interactive or non-interactive formats ^[3]. State Medicaid requirements, CMS regulations, and medical policies supersede both criterion sets when applicable ^[15].

How to use InterQual Criteria effectively

Utilization review nurses apply the criteria as first-level screening tools by comparing submitted documentation against established clinical thresholds ^[2]. The richness of clinical detail within the framework permits consideration of individual patient severity of illness, comorbidities, and complications during the review process in real time ^[2]. Cases meeting the specified criteria receive approval, whereas cases falling short undergo referral to medical directors or physician reviewers for secondary evaluation ^[2].

Clinical judgment remains paramount throughout the review process. The criteria function as supplementary decision support tools rather than absolute determinants, recognizing that standardized guidelines cannot address every clinical situation or apply universally to all patients ^[2]. Reviewers must acknowledge that criteria alone cannot deny cases, as only physicians retain authority to determine clinical appropriateness ^[2].

Healthcare organizations may establish exceptions reflecting organizational needs such as legislative requirements or geographic differences ^[16]. Episode Day criteria exceptions allow primary reviewers to utilize all clinical information received from a hospital stay rather than restricting evaluation to day-one clinical data exclusively ^[16]. Admission reviews for residential treatment centers, long-term acute care facilities, and skilled nursing facilities may accept clinical information obtained up to three days prior to admission date ^[16].

Annual criterion updates require careful review by clinical staff to identify enhancements and modifications affecting review processes ^[17]. Organizations benefit from tracking denial rates and rework time surrounding prior authorization to measure whether documentation and workflow improvements produce measurable results ^[18].

References

[1] – https://pmc.ncbi.nlm.nih.gov/articles/PMC9353653/
[2] – https://www.priorityhealth.com/provider/manual/standards/utilization-management-program/interqual-loc-criteria
[3] – https://nursefern.com/remote-nurses-guide-to-mcg-and-interqual/
[4] – https://marketplace.optum.com/content/dam/change-healthcare/marketplace-assets/InterQual_Criteria._Download.pdf
[5] – http://sites.mckesson.com/MHS/PDFs/FS_InterQual_Delivery_Options.pdf
[6] – https://provider.massgeneralbrighamhealthplan.org/Areas/Resources/Content/Documents/InterqualGuide.docx
[7] – https://www.point32health.org/documents/interqual-medical-review-tip-sheet-es
[8] – https://www.nhpri.org/blobnhpri08e0944faa/wp-content/uploads/2024/05/IQC-Online-conduct-a-level-of-care-review-job-aid.pdf
[9] – https://provider.excellusbcbs.com/documents/d/global/exc-prv-level-of-care-criteria-for-inpatient-residential-partial-hospital-and-intensive-outpatient-mental-health-services-for-adults-and-children
[10] – https://www.studocu.com/en-us/document/western-governors-university/informatics-for-transforming-nursing-care/inter-qual-criteria-summary/105274594
[11] – https://positivehealthcare.net/wp-content/uploads/2023/12/Services-Reviewed-Using-IQ.pdf
[12] – https://providers.anthem.com/docs/gpp/KY_CAID_InterQualMCGCareGuidelines.pdf?v=202212081628
[13] – https://www.acpadvisors.org/index.php?option=com_dailyplanetblog&view=entry&year=2023&month=10&day=11&id=58:use-and-abuse-of-screening-criteria
[14] – https://apprisemd.com/a-quiet-shift-that-could-shake-up-hospital-utilization-review/
[15] – https://www.wellpoint.com/content/dam/digital/wellpoint/documents/provider/maryland/government/general/MDWP_CAID_Feb2023CUMG.pdf
[16] – https://www.bcbsnd.com/providers/news-resources/healthcare-news/2025-interqual-criteria-implementation
[17] – https://provcomm.amerihealth.com/pnc-ah/Items/25-0140_AHA_InterQual_summary_2025.pdf
[18] – https://getsolum.com/glossary/interqual-mcg-criteria-guide