Summary & Overview
HCPCS Level II H0035: Mental Health Partial Hospitalization, <24 Hours
HCPCS Level II code H0035 represents mental health partial hospitalization services provided for periods shorter than 24 hours. As an ambulatory, program-based psychiatric treatment option, the code captures day-treatment models that deliver intensive, multidisciplinary care without inpatient admission. Nationally, partial hospitalization occupies a key role in the continuum of behavioral health services by offering a higher level of support than outpatient therapy while avoiding inpatient hospitalization.
Major commercial payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, and UnitedHealthcare. Readers will find an overview of coverage implications under those payers, common clinical contexts for use, and how H0035 relates to other behavioral health service codes used in ambulatory and day-treatment settings. The publication outlines coding considerations, typical sites of service, and associated service lines to help clarify documentation and billing workflows. It also highlights where input data is missing and flags items requiring payer-specific policy review.
Content is oriented to national stakeholders including billing professionals, behavioral health clinicians, and policy analysts seeking concise guidance on code definition, service setting, and practical coding relationships. Data not available in the input is noted where applicable.
Billing Code Overview
HCPCS Level II code H0035 describes mental health partial hospitalization, treatment, less than 24 hours. This service type is psychiatric partial hospitalization, providing structured, intensive mental health treatment during the day without an overnight stay. Typical sites of service include hospital outpatient departments (POS 19) and community mental health centers (POS 53). This code denotes a programmatic level of care designed to deliver multidisciplinary psychiatric services in a concentrated, non-residential setting.
Clinical & Coding Specifications
Clinical Context
A 42-year-old patient with a mood disorder due to a known physiological condition (F06.31) is referred to a psychiatric partial hospitalization program for intensive daytime treatment when symptoms escalate but inpatient admission is not required. The patient presents to the hospital outpatient department (POS 19) for intake evaluation in the morning, receives structured therapeutic activities, medication management, and group psychotherapy over several hours, then returns home the same day. The interdisciplinary team includes a psychiatry physician, clinical social worker, psychologist, and mental health counselor who document daily treatment, coordinate care with the referring provider, and monitor progress for possible transition to outpatient psychotherapy or higher level of care.
Coding Specifications
HCPCS Level II code H0035 represents mental health partial hospitalization, treatment, less than 24 hours. Common modifiers listed and their usage:
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59- Distinct Procedural Service -
Use when two procedures/services not normally reported together are performed on the same day and are distinct or independent from each other.
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76- Repeat Procedure by Same Physician -
Use when the same service is repeated by the same provider on the same day.
Associated provider taxonomies and specialties: