PR-100 / CO-100: Payer paid the patient, not the practice
Triage: Bill the patient immediately
By Dr. Daniel Turner, DC · Reviewed September 2, 2026
What does denial code PR-100 / CO-100 mean?
The payer sent the money to the patient instead of the practice, most often on out of network claims. Nothing further is coming from the payer on this line; the patient is holding your reimbursement.
What does PR-100 / CO-100 usually mean in a chiropractic office?
This code hides in remittances looking like a denial, gets written off by busy billers, and quietly becomes the most expensive misread in the book. The claim was not denied. It was paid, to the wrong party.
How do you fix a PR-100 / CO-100 denial?
- Bill the patient for the amount now, referencing the payer payment sent to them.
- Call rather than mail; recovery odds fall quickly once the check is spent.
- If out of network paid-to-patient is a pattern with a payer, consider assignment of benefits language and network strategy.
What this looks like in practice
An out of network claim for $240 processes, and the payer sends the check to the patient. The ERA line shows code 100 with nothing payable to the practice. A busy biller reads it as a denial and writes it off. The patient has the practice’s $240 and does not know it, and every week that passes makes the recovery call harder.
How to stop it from happening again
- ✓Treat any 100 code as money in the wrong pocket, never as a denial
- ✓Call the patient the week the ERA posts; recovery odds fall with every statement cycle
- ✓For repeat offenders among payers, revisit assignment of benefits language and network strategy
How Cervica handles PR-100 / CO-100
Cervica reads the 100 code off the ERA and routes it to patient billing instead of the write off pile, with the reference language ready.
Related codes
- →CO-45 · Charge exceeds fee schedule
- →PR-242 / CO-242 · Out of network
Quick answers
What does denial code PR-100 / CO-100 mean?
The payer sent the money to the patient instead of the practice, most often on out of network claims. Nothing further is coming from the payer on this line; the patient is holding your reimbursement.
What does PR-100 / CO-100 usually mean in a chiropractic office?
This code hides in remittances looking like a denial, gets written off by busy billers, and quietly becomes the most expensive misread in the book. The claim was not denied. It was paid, to the wrong party.
How do you fix a PR-100 / CO-100 denial?
Bill the patient for the amount now, referencing the payer payment sent to them. Call rather than mail; recovery odds fall quickly once the check is spent. If out of network paid-to-patient is a pattern with a payer, consider assignment of benefits language and network strategy.
General information for billing teams, not legal or payer specific advice. CARC definitions belong to X12; payer policies vary and control. Verify against the payer contract before acting on any individual claim.