G0378 — Hospital observation service, per hour
G0378 is a HCPCS Level II code for hospital observation service, per hour. It belongs to the Procedures and Professional Services (Temporary) section. Whether Medicare pays it depends on the coverage rule below.
Medicare coverage: Special coverage instructions apply
There are published conditions attached to this code. Check the applicable coverage policy before billing it: the code being valid is not the same as the service being covered.
From the coverage field of the CMS Alpha-Numeric HCPCS File, release 2026Q3-Jul. This states Medicare’s position on the code, not on your particular claim.
Physician fee schedule statusX
Statutory exclusion. The item or service is not within the statutory definition of 'physician services', so the fee schedule never pays it.
Global period: XXX
Want the dollar amount for your locality? The fee calculator applies your GPCI and the current conversion factor.
Medically Unlikely Edits — units per day
The most units of G0378 Medicare will pay on one date of service. Bill more on a single line and it is denied. The limit is not the same in every setting, so the row that matters is the one matching the claim you are building.
- practitioner
- 0 — never payable MAI 3 — Date of Service Edit: Clinical · CMS Policy
- outpatient
- 72 units MAI 3 — Date of Service Edit: Clinical · Clinical: Data
The adjudication indicator decides whether exceeding the limit is worth appealing at all: MAI 1 is a line edit you can support with documentation, MAI 3 is a date-of-service edit that is also appealable, and MAI 2 is absolute — no documentation overrides it. CMS MUE 2026Q3.
The CMS record for G0378
- Long descriptor
- Hospital observation service, per hour
- Short descriptor
- Hospital observation per hr
- Added
- January 1, 2006
- BETOS
- M2A
- Pricing indicator
- 00 — Not priced by Part B
The official wording. This is what the code means.
CMS's 28-character form, which is what shows up on a remittance advice.
When CMS introduced the code.
Berenson-Eggers Type of Service — CMS's own analytic grouping.
Service not separately priced by Part B — not covered, bundled into another service, or used by Part A only.
Codes adjacent to G0378
HCPCS has no hierarchy — related items simply sit next to each other in the numbering. If G0378 is not quite right, the correct code is very often within a few positions of it.
- G0339Image-guided robotic linear accelerator-based stereotactic radiosurgery, complete course of therapy in one session or first session of fractionated treatment
- G0340Image-guided robotic linear accelerator-based stereotactic radiosurgery, delivery including collimator changes and custom plugging, fractionated treatment, all lesions, per session, second through fifth sessions, maximum five sessions per course of treatment
- G0341Percutaneous islet cell transplant, includes portal vein catheterization and infusion
- G0342Laparoscopy for islet cell transplant, includes portal vein catheterization and infusion
- G0343Laparotomy for islet cell transplant, includes portal vein catheterization and infusion
- G0364Bone marrow aspiration performed with bone marrow biopsy through the same incision on the same date of serviceterminated
- G0365Vessel mapping of vessels for hemodialysis access (services for preoperative vessel mapping prior to creation of hemodialysis access using an autogenous hemodialysis conduit, including arterial inflow and venous outflow)terminated
- G0372Physician service required to establish and document the need for a power mobility device
- G0379Direct admission of patient for hospital observation care
- G0380Level 1 hospital emergency department visit provided in a type b emergency department; (the ed must meet at least one of the following requirements: (1) it is licensed by the state in which it is located under applicable state law as an emergency room or emergency department; (2) it is held out to the public (by name, posted signs, advertising, or other means) as a place that provides care for emergency medical conditions on an urgent basis without requiring a previously scheduled appointment; or (3) during the calendar year immediately preceding the calendar year in which a determination under 42 cfr 489.24 is being made, based on a representative sample of patient visits that occurred during that calendar year, it provides at least one-third of all of its outpatient visits for the treatment of emergency medical conditions on an urgent basis without requiring a previously scheduled appointment)
- G0381Level 2 hospital emergency department visit provided in a type b emergency department; (the ed must meet at least one of the following requirements: (1) it is licensed by the state in which it is located under applicable state law as an emergency room or emergency department; (2) it is held out to the public (by name, posted signs, advertising, or other means) as a place that provides care for emergency medical conditions on an urgent basis without requiring a previously scheduled appointment; or (3) during the calendar year immediately preceding the calendar year in which a determination under 42 cfr 489.24 is being made, based on a representative sample of patient visits that occurred during that calendar year, it provides at least one-third of all of its outpatient visits for the treatment of emergency medical conditions on an urgent basis without requiring a previously scheduled appointment)
- G0382Level 3 hospital emergency department visit provided in a type b emergency department; (the ed must meet at least one of the following requirements: (1) it is licensed by the state in which it is located under applicable state law as an emergency room or emergency department; (2) it is held out to the public (by name, posted signs, advertising, or other means) as a place that provides care for emergency medical conditions on an urgent basis without requiring a previously scheduled appointment; or (3) during the calendar year immediately preceding the calendar year in which a determination under 42 cfr 489.24 is being made, based on a representative sample of patient visits that occurred during that calendar year, it provides at least one-third of all of its outpatient visits for the treatment of emergency medical conditions on an urgent basis without requiring a previously scheduled appointment)
- G0383Level 4 hospital emergency department visit provided in a type b emergency department; (the ed must meet at least one of the following requirements: (1) it is licensed by the state in which it is located under applicable state law as an emergency room or emergency department; (2) it is held out to the public (by name, posted signs, advertising, or other means) as a place that provides care for emergency medical conditions on an urgent basis without requiring a previously scheduled appointment; or (3) during the calendar year immediately preceding the calendar year in which a determination under 42 cfr 489.24 is being made, based on a representative sample of patient visits that occurred during that calendar year, it provides at least one-third of all of its outpatient visits for the treatment of emergency medical conditions on an urgent basis without requiring a previously scheduled appointment)
- G0384Level 5 hospital emergency department visit provided in a type b emergency department; (the ed must meet at least one of the following requirements: (1) it is licensed by the state in which it is located under applicable state law as an emergency room or emergency department; (2) it is held out to the public (by name, posted signs, advertising, or other means) as a place that provides care for emergency medical conditions on an urgent basis without requiring a previously scheduled appointment; or (3) during the calendar year immediately preceding the calendar year in which a determination under 42 cfr 489.24 is being made, based on a representative sample of patient visits that occurred during that calendar year, it provides at least one-third of all of its outpatient visits for the treatment of emergency medical conditions on an urgent basis without requiring a previously scheduled appointment)
- G0389Ultrasound b-scan and/or real time with image documentation; for abdominal aortic aneurysm (aaa) screeningterminated
- G0390Trauma response team associated with hospital critical care service
Questions about G0378
What is HCPCS code G0378?
G0378 is a HCPCS Level II code for hospital observation service, per hour. It sits in the Procedures and Professional Services (Temporary) section.
Does Medicare cover G0378?
The CMS HCPCS file marks G0378 as "Special coverage instructions apply". There are published conditions attached to this code. Check the applicable coverage policy before billing it: the code being valid is not the same as the service being covered.
How is G0378 paid under the physician fee schedule?
G0378 carries PFS status code X. Statutory exclusion. The item or service is not within the statutory definition of 'physician services', so the fee schedule never pays it.