G0400 HCPCS code: Home sleep test (hst) with type iv portable monitor, unattended; minimum of 3 channels

G0400 is the HCPCS Level II code for home sleep test (hst) with type iv portable monitor, unattended; minimum of 3 channels. In 2024 Medicare paid an average of $138.06 per service for G0400 across 28,180 services. Its Medicare coverage code is C (Carrier judgment): Coverage is decided by the Medicare contractor (MAC) case by case. The NCCI unit limit is 1 per day on outpatient hospital claims. Medicare volume rose 385% from 2022 to 2024 (5,809 to 28,180 services). In 2024, about 393 clinicians billed Medicare for G0400 for 26,641 beneficiaries; Illinois, New York, Washington accounted for 79% of services.

Code details

Who bills G0400 (2024)

Counts only. Supplier and clinician names, contact lists and state-by-state detail are in Caduvo.

Medicare utilization for G0400, 2022–2024

States with the most G0400 services (2024)

NCCI unit limits (MUE)

Medicare policy articles for this code

• A53019: Polysomnography and Sleep Studies – Medical Policy Article (National Government Services, Inc. (MAC - Part A, MAC - Part B))
• A56903: Billing and Coding: Polysomnography and Other Sleep Studies (WPS Insurance Corporation (MAC - Part A, MAC - Part B))
• A56923: Billing and Coding: Outpatient Sleep Studies (Novitas Solutions, Inc. (MAC - Part A, MAC - Part B))
• A56995: Billing and Coding: Polysomnography (Palmetto GBA (MAC - Part A, MAC - Part B))
• A57049: Billing and Coding: Polysomnography and Other Sleep Studies (CGS Administrators, LLC (MAC - Part A, MAC - Part B))
• A57496: Billing and Coding: Polysomnography and Sleep Testing (First Coast Service Options, Inc. (MAC - Part A, MAC - Part B))
• A57697: Billing and Coding: Polysomnography and Other Sleep Studies (Noridian Healthcare Solutions, LLC (MAC - Part A, MAC - Part B))
• A58559: Billing and Coding: Independent Diagnostic Testing Facilities (IDTF) (Palmetto GBA (MAC - Part B))

Covered diagnoses (87 ICD-10-CM codes)

The diagnoses most often listed as covered in the policy articles above:

Showing 10 of 87. The full list, non-covered diagnoses and CSV export are in Caduvo.

What changed for G0400

• 2008-03-13: G0400 added to HCPCS Level II
• Next scheduled CMS quarterly update (HCPCS and DMEPOS fee schedule): 2027-01-01

Frequently asked questions

What is HCPCS code G0400?

G0400 is the HCPCS Level II code for home sleep test (hst) with type iv portable monitor, unattended; minimum of 3 channels. Short descriptor: "Home sleep test/type 4 porta".

How much does Medicare pay for G0400?

In 2024, the average Medicare payment was $138.06 per service (average allowed $175.35).

Does Medicare cover G0400?

Coverage code C — Carrier judgment. Coverage is decided by the Medicare contractor (MAC) case by case.

Which diagnoses support coverage for G0400?

Medicare policy articles that cite G0400 list 87 covered ICD-10-CM diagnosis codes across 8 articles. The most cited include G47.10 (Hypersomnia, unspecified), G47.11 (Idiopathic hypersomnia with long sleep time), G47.12 (Idiopathic hypersomnia without long sleep time). A listed diagnosis is necessary but not sufficient; the policy's other criteria still apply.

How many units of G0400 can be billed per day?

1 on outpatient hospital claims; 1 on practitioner claims (NCCI medically unlikely edits).

Related G04 codes

• G0402 — Initial preventive physical examination; face-to-face visit, services limited to new beneficiary during the first 12 months of medicare enrollment
• G0403 — Electrocardiogram, routine ecg with 12 leads; performed as a screening for the initial preventive physical examination with interpretation and report
• G0404 — Electrocardiogram, routine ecg with 12 leads; tracing only, without interpretation and report, performed as a screening for the initial preventive physical examination
• G0405 — Electrocardiogram, routine ecg with 12 leads; interpretation and report only, performed as a screening for the initial preventive physical examination
• G0406 — Follow-up inpatient consultation, limited, physicians typically spend 15 minutes communicating with the patient via telehealth
• G0407 — Follow-up inpatient consultation, intermediate, physicians typically spend 25 minutes communicating with the patient via telehealth
• G0408 — Follow-up inpatient consultation, complex, physicians typically spend 35 minutes communicating with the patient via telehealth
• G0409 — Social work and psychological services, directly relating to and/or furthering the patient's rehabilitation goals, each 15 minutes, face-to-face; individual (services provided by a corf-qualified social worker or psychologist in a corf)
• G0410 — Group psychotherapy other than of a multiple-family group, in a partial hospitalization or intensive outpatient setting, approximately 45 to 50 minutes
• G0411 — Interactive group psychotherapy, in a partial hospitalization or intensive outpatient setting, approximately 45 to 50 minutes
• G0412 — Open treatment of iliac spine(s), tuberosity avulsion, or iliac wing fracture(s), unilateral or bilateral for pelvic bone fracture patterns which do not disrupt the pelvic ring includes internal fixation, when performed
• G0413 — Percutaneous skeletal fixation of posterior pelvic bone fracture and/or dislocation, for fracture patterns which disrupt the pelvic ring, unilateral or bilateral, (includes ilium, sacroiliac joint and/or sacrum)

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Next steps

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Sources: CMS HCPCS Level II release October 2025; CMS DMEPOS fee schedule; CMS NCCI MUE tables; CMS Medicare utilization (physician and DME supplier files); CMS Medicare Coverage Database articles. Fees are Medicare allowables, not commercial rates. Not billing or legal advice.

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