HCPCS Level II modifier
Modifier M2
Modifier M2 is a HCPCS Level II modifier. CMS describes it as: Medicare secondary payer (MSP).
Source: CMS HCPCS Level II, October 2026 file dated September 23, 2026. Publisher page
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- Modifier
- M2
- Type
- HCPCS Level II modifier, maintained by CMS
- CMS description
- Medicare secondary payer (MSP)
- 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
- MAOrdering professional is not required to consult a clinical decision support mechanism due to service being rendered to a patient with a suspected or confirmed emergency medical condition
- LUFractionated payment
- MBOrdering professional is not required to consult a clinical decision support mechanism due to the significant hardship exception of insufficient internet access
- LTLeft side (used to identify procedures performed on the left side of the body)
- MCOrdering professional is not required to consult a clinical decision support mechanism due to the significant hardship exception of electronic health record or clinical decision support mechanism vendor issues
- LSFDA-monitored intraocular lens implant
- MDOrdering professional is not required to consult a clinical decision support mechanism due to the significant hardship exception of extreme and uncontrollable circumstances
- LRLaboratory round trip
Related pages
Questions
What does modifier M2 mean?
Modifier M2 is a HCPCS Level II modifier. CMS describes it as: Medicare secondary payer (MSP).
Is modifier M2 a CPT or a HCPCS modifier?
M2 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 M2 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.