H0031 is a HCPCS Level II code for "mental health assessment, by non-physician." It lives in the H-code range that CMS created primarily for state Medicaid agencies and behavioral health programs, which means its practical rules — who may bill it, what an assessment must include, and how a unit is defined — are set state by state and plan by plan rather than by a single national standard. In most programs it covers structured intake, diagnostic, or periodic reassessment work performed by licensed or credentialed non-physician behavioral health professionals.
Use H0031 when a state Medicaid program, Medicaid MCO, or behavioral health carve-out contract designates it as the code for a non-physician mental health assessment — commonly the comprehensive intake assessment at admission to services, court- or program-mandated assessments, or scheduled reassessments that update the diagnosis and treatment plan. Confirm three things against the specific payer’s manual before billing: the eligible provider types (for example LCSW, LPC, LMFT, psychologist, or credentialed QMHP, depending on the state), the unit definition (per assessment/encounter in some states, per 15 minutes in others), and any frequency limits per year or per episode of care.
Do not bill H0031 to Medicare — traditional Medicare does not pay H-codes; the psychiatric diagnostic evaluation is reported with CPT 90791 instead. Do not use it for a physician’s or prescriber’s diagnostic evaluation where the program expects 90791/90792 or an E/M code. Do not report it for ongoing psychotherapy sessions, case management, or treatment planning that has its own code in the payer’s fee schedule. And do not assume unit rules transfer between states or between plans in the same state — billing an encounter-based definition in 15-minute units (or the reverse) is a common source of overpayments and takebacks.
The assessment document should include the referral reason, psychosocial history, mental status examination, risk assessment, diagnostic impression with DSM/ICD coding, and the resulting recommendations or treatment plan — matching whatever content elements the state’s program manual specifies. Record the assessor’s credential and, where the payer defines time-based units, the start/stop times or total duration. Programs frequently require the assessment to be completed and signed within a defined window of admission, so dates and signatures matter as much as content.
No. Traditional Medicare does not reimburse HCPCS H-codes. A diagnostic mental health evaluation for a Medicare patient is reported with CPT 90791 (or 90792 when medical services are included) by an eligible provider type.
It depends entirely on the state or plan. Some Medicaid programs define one unit as the complete assessment encounter; others define 15-minute units with a maximum per assessment. The payer’s fee schedule or provider manual is the only reliable source — never carry a unit convention from one contract to another.
Eligible provider types are set by each state program — typically licensed non-physician behavioral health professionals such as psychologists, LCSWs, LPCs, and LMFTs, and in some states credentialed qualified mental health professionals working under supervision. Verify the credential list in the specific program manual.
No. They describe the same category of service in different code systems, and billing both for one assessment is duplicate billing. Which one to use is dictated by the payer: H0031 where the Medicaid program or MCO specifies it, 90791 where CPT coding applies.
Coding questions like this one are where revenue leaks start. See how Medtransic supports mental health practices with certified billing and denial management: Mental Health Billing Services.