Summary & Overview
HCPCS Level II S9128: Speech Therapy, In-Home, Per Diem
HCPCS Level II code S9128 denotes per‑diem speech therapy services delivered in the patient’s home. The code identifies home-based speech-language pathology interventions that address communication and swallowing disorders and supports billing and utilization tracking for outpatient/home health programs nationwide. Its use matters nationally as home-based therapy has grown in importance for post‑acute care, chronic condition management, and access for patients with mobility limitations. Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, and UnitedHealthcare. Readers will learn what S9128 represents clinically and operationally, how it relates to other home-based speech therapy billing options, and the practical context for correct coding and billing workflows. The publication summarizes common clinical indications associated with the service (for example, aphasia, dysphagia, apraxia, and language disorders), contrasts S9128 with time‑based or encounter‑based billing alternatives, and highlights common modifiers and related procedure codes where applicable. Where input fields were incomplete, the document notes missing metadata explicitly. This summary provides clinicians, coders, and policy stakeholders with a concise reference to inform coding choices, claims processing, and program design for home‑based speech therapy services at a national level.
Billing Code Overview
HCPCS Level II code S9128 describes speech therapy, provided in the home, billed per diem. The code represents a home health service delivering speech-language pathology interventions to patients in their residence. This service type is speech therapy / home health service, and the typical site of service is the home.
Clinical & Coding Specifications
Clinical Context
A 72-year-old homebound patient with post-stroke expressive aphasia and mild dysphagia receives speech therapy visits at home billed as HCPCS Level II code S9128 (speech therapy, in the home, per diem). The patient is under a speech-language pathology plan of care established by a licensed Speech-Language Pathologist. A home health agency coordinates visits; each visit includes goals review, therapeutic exercises for language and swallowing, caregiver education, and functional communication practice. Documentation includes the plan of care, objective measures of progress, time on skilled tasks, care team communications, and any safety observations during the home visit.
Coding Specifications
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Common Modifiers
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GN: Services delivered under an outpatient speech-language pathology plan of care — used when speech services are furnished according to an established outpatient SLP plan of care and need to identify the therapy discipline. -
59: Distinct Procedural Service — used when a separate and distinct speech therapy service is provided on the same day as another procedure and the services are not normally billed together. -
Associated Provider Taxonomies
| Taxonomy Code | Specialty |
|---|---|
235Z00000X | Speech-Language Pathologist |
225X00000X | Rehabilitation Practitioner |
251E00000X | Home Health Agency |
Related Diagnoses
R47.01— Aphasia
Aphasia impacts language comprehension and expression; speech therapy in the home addresses functional communication and language rehabilitation relevant to S9128.
F80.0— Phonological disorder
Phonological disorder affects speech sound production and may require skilled speech therapy interventions delivered in the home under S9128.
R13.10— Dysphagia, unspecified
Dysphagia involves swallowing impairment; home-based speech therapy can include swallowing assessment and interventions that justify billing S9128.
F80.2— Mixed receptive-expressive language disorder
Mixed receptive-expressive language disorder involves both understanding and expressive deficits; these impairments are treated with targeted SLP services provided in the home under S9128.
R48.2— Apraxia
Apraxia of speech is a motor planning disorder; skilled SLP treatment performed at home is clinically relevant to S9128.
Related Codes
| Code | Description | Relationship to S9128 |
|---|---|---|
G0153 | Services of a speech and language pathologist in home health or hospice settings, each 15 minutes | Used for time-based, quarter-hour reporting of SLP skilled time in home health; can be used alongside or instead of per diem reporting depending on payer rules. |
S9152 | Speech therapy, re‑evaluation | Used when a formal re-evaluation of speech-language function is performed; may be used when updating the plan of care that supports continued S9128 billing. |
National Reimbursement Benchmarks
National mean rates for HCPCS Level II code S9128 show commercial payers generally above Medicare and below the BUCA average. BUCA (average commercial) has a mean rate of $103.42 compared with Medicare at $0.00; Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Aetna have means of $75.34, $199.72, $79.01, and $37.98 respectively.
Rate dispersion (P75 minus P25) is tightest for Aetna (38 − 38 = 0) and Cigna Health (212 − 212 = 0), indicating no reported spread in the input percentiles. Dispersion is widest for BUCA (165 − 38 = 127) and Blue Cross Blue Shield (108 − 30 = 78). The table and chart below present the full breakdown.
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