HCPCS Level II modifier
Modifier UG
Modifier UG is a HCPCS Level II modifier. CMS describes it as: Services provided in the afternoon.
Source: CMS HCPCS Level II, October 2026 file dated September 23, 2026. Publisher page
Run it in Rivvi
Check the codes on your claims export
Upload a claims export. Rivvi flags ICD-10 and HCPCS codes that are not billable or are replaced. It does not check modifiers.
Check my exportFree to start. Opens Rivvi, the AI workspace for healthcare teams.
- Modifier
- UG
- Type
- HCPCS Level II modifier, maintained by CMS
- CMS description
- Services provided in the afternoon
- Claim form
- CMS-1500 item 24D, up to four modifiers per line. 837P SV101-3 to SV101-6.
- Guidance
- CMS HCPCS quarterly update
Related modifiers
- UHServices provided in the evening
- UFServices provided in the morning
- UJServices provided at night
- UEUsed durable medical equipment
- UKServices provided on behalf of the client to someone other than the client (collateral relationship)
- UDMedicaid level of care 13, as defined by each state
- UNTwo patients served
- UCMedicaid level of care 12, as defined by each state
Related pages
Questions
What does modifier UG mean?
Modifier UG is a HCPCS Level II modifier. CMS describes it as: Services provided in the afternoon.
Is modifier UG a CPT or a HCPCS modifier?
UG is a HCPCS Level II modifier from the CMS quarterly HCPCS file. Two-digit numeric modifiers, such as 25 or 59, are CPT modifiers.
Where does modifier UG go on a claim?
On the CMS-1500 it goes in item 24D next to the procedure code. Each line holds up to four modifiers. On an 837P it goes in SV101-3 to SV101-6.
What denial comes back when a modifier is wrong?
A missing or mismatched modifier often comes back as CARC 4. A modifier that was not valid on the date of service comes back as CARC 182. A bundling edit the modifier should have bypassed comes back as CARC 97 or 236.