Box 9 and 9a to 9d: Other insured information
By Dr. Daniel Turner, DC · Reviewed September 2, 2026
What goes in Box 9 and 9a to 9d of the CMS-1500?
Details of secondary coverage when another policy also covers the patient: the other insured’s name, policy or group number, and plan name. Completed when Box 11d says another health plan exists.
What does Box 9 and 9a to 9d mean for chiropractic billing?
This is the coordination of benefits box. Skipping it when a spouse’s plan also covers the patient invites the payer to pend or deny while it hunts for primacy. Ask about all coverage at intake and at every January re-verification.
The mistakes that turn this box into denials
- ✗Leaving it empty when 11d is marked yes
- ✗Stale secondary details from a plan that termed
The denials this box causes
- →CO-22 · see the full fix in the denial library
How Cervica fills Box 9 and 9a to 9d
Cervica generates the CMS-1500 and its electronic 837P equivalent from the chart and the payer's own rules: identifiers from the verified insurance record, modifiers and codes per payer, and pre submission scrubbing that flags exactly the mistakes listed above before a claim leaves the building.
Related boxes
- →Box 11 and 11a to 11d · Insured policy group number and related details
General information for billing teams, not billing advice for any individual claim. The NUCC's 1500 Claim Form instructions and each payer's companion guides control.