G-Codes

Home health agencies bill Medicare on institutional claims (Type of Bill 32X), not on professional CPT claims. Each visit appears as a separate line item carrying a revenue code that identifies the discipline, a G-code that identifies the specific service, the visit date, and units reported in 15-minute increments. The G-code tells the Medicare Administrative Contractor (MAC) who delivered the visit and what kind of service it was: direct skilled care, observation and assessment, management and evaluation, or training and education. This detail feeds payment logic. Per-visit payments for Low Utilization Payment Adjustment (LUPA) periods and outlier calculations both depend on the discipline reported on each line.

The codes agencies use most often map to the six home health disciplines:

• G0299 and G0300: direct skilled care by a registered nurse (RN) or licensed practical nurse (LPN)
• G0151, G0152, and G0153: physical therapy, occupational therapy, and speech-language pathology
• G0157 and G0158: services of a physical therapist assistant or occupational therapy assistant
• G0155: medical social work services
• G0156: home health aide services
• G0493 and G0494: skilled observation and assessment by an RN or LPN

Separate codes exist for management and evaluation of the plan of care and for training and education, so the billed code should match what the visit note actually describes.

For a normal 30-day period, payment is driven by the HIPPS code, so G-codes can look like formalities. They are not. If a period falls below the LUPA threshold, Medicare pays each visit line at the national per-visit rate for the discipline on that G-code, so an LPN visit coded as an RN visit is an overpayment. Outlier payments are calculated from wage-adjusted per-visit amounts tied to the reported visits. In medical review, contractors compare each billed G-code against the visit note. A claim line for skilled observation supported by a note describing routine care invites a line denial and can pull the whole claim into deeper scrutiny.

Most G-code errors are process failures rather than knowledge gaps:

• Coding LPN or therapy assistant visits under the RN or therapist codes, which misstates both payment and staffing patterns
• Units that do not match the documented time in and time out
• Billing a visit type the note does not support, such as management and evaluation without evidence of care plan oversight
• Missing or mismatched revenue code and G-code pairs that trigger claim edits

Agencies with strong clean claim rates validate the G-code, revenue code, units, and visit documentation together before the final claim is released, not after a rejection.