HCPCS Level II modifier
Modifier PO
Modifier PO is a HCPCS Level II modifier. CMS describes it as: Excepted service provided at an off-campus, outpatient, provider-based department of a hospital.
Source: CMS HCPCS Level II, October 2026 file dated September 23, 2026. Publisher page
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- Modifier
- PO
- Type
- HCPCS Level II modifier, maintained by CMS
- CMS description
- Excepted service provided at an off-campus, outpatient, provider-based department of a hospital
- 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
- PSPositron emission tomography (PET) or PET/computed tomography (CT) to inform the subsequent treatment strategy of cancerous tumors when the beneficiary's treating physician determines that the PET study is needed to inform subsequent anti-tumor strategy
- PNNon-excepted service provided at an off-campus, outpatient, provider-based department of a hospital
- PTColorectal cancer screening test; converted to diagnostic test or other procedure
- PMPost mortem
- Q0Investigational clinical service provided in a clinical research study that is in an approved clinical research study
- PLProgressive addition lenses
- Q1Routine clinical service provided in a clinical research study that is in an approved clinical research study
- PIPositron emission tomography (PET) or PET/computed tomography (CT) to inform the initial treatment strategy of tumors that are biopsy proven or strongly suspected of being cancerous based on other diagnostic testing
Related pages
Questions
What does modifier PO mean?
Modifier PO is a HCPCS Level II modifier. CMS describes it as: Excepted service provided at an off-campus, outpatient, provider-based department of a hospital.
Is modifier PO a CPT or a HCPCS modifier?
PO 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 PO 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.