Yes, per CMS. Its Medicare Secondary Payer (MSP) booklet tells providers to "Gather accurate MSP data by asking patients or their representatives questions about other (potential) health insurance coverage that could be primary to Medicare at each visit before providing services," and to "Check eligibility to verify whether other primary insurance information exists." That's on top of the baseline rule: "Medicare provisions require providers to determine the primary or secondary payer of benefits for patient items or services before submitting claims."
The baseline rule
From CMS's MSP booklet (MLN006903, July 2025):
CMS: "Medicare provisions require providers to determine the primary or secondary payer of benefits for patient items or services before submitting claims."
The key words are before submitting claims. You work out the payer order first, not after a claim goes out.
Who pays first
CMS describes the default and notes that it isn't absolute:
CMS: "We pay first for patients who don't have other primary insurance or coverage primary to Medicare. In certain situations, we may pay first when the patient has other primary insurance coverage."
Because there are "certain situations," the questions matter. The answer can depend on the patient's other coverage.
Ask at each visit and check eligibility
This is CMS's responsibility line for all providers:
CMS: "Gather accurate MSP data by asking patients or their representatives questions about other (potential) health insurance coverage that could be primary to Medicare at each visit before providing services. Check eligibility to verify whether other primary insurance information exists."
Two separate actions are in there: ask (at each visit, before services) and check eligibility.
Institutional providers only. CMS adds a line specifically for institutional providers: "Review or administer the MSP questions each time you treat or admit the patient." It's listed under institutional providers in the booklet, so don't treat it as a rule for every provider type.
On the claim
CMS: "Identify all known primary payers to Medicare on the claim. Bill any primary payer before billing Medicare."
What CMS says happens if the record shows another primary payer
The booklet is direct about this:
CMS: "if the patient's CWF MSP record shows another insurer should pay primary to Medicare, we deny the claim."
It also states, in CMS's own words:
CMS: "Federal law allows Medicare to recover incorrect payments. We require you to return any payment we incorrectly paid as the primary payer."
A front-desk checklist
These steps restate CMS's lines above as a list. They're not extra rules:
- Ask at each visit, before services, about other coverage that could be primary to Medicare (CMS).
- Check eligibility for other primary insurance information (CMS).
- Put every known primary payer on the claim, and bill any primary payer before billing Medicare (CMS).
- Institutional providers: review or administer the MSP questions each time you treat or admit the patient (CMS, institutional providers only).
When in doubt, check the source and your MAC.
FAQ
How often should we ask Medicare patients about other insurance?
CMS: "Gather accurate MSP data by asking patients or their representatives questions about other (potential) health insurance coverage that could be primary to Medicare at each visit before providing services."
When does Medicare pay first?
CMS: "We pay first for patients who don't have other primary insurance or coverage primary to Medicare. In certain situations, we may pay first when the patient has other primary insurance coverage."
Do we bill the primary payer before Medicare?
CMS: "Identify all known primary payers to Medicare on the claim. Bill any primary payer before billing Medicare."
What if the patient's MSP record shows another insurer is primary?
CMS: "if the patient's CWF MSP record shows another insurer should pay primary to Medicare, we deny the claim."
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Source: CMS, MLN006903, Medicare Secondary Payer (MLN booklet, July 2025). All quotes above are from this booklet.