Denial Code 101 (CO-101, PR-101) — Meaning & What to Do
Claim Adjustment Reason Code (CARC)
What denial code 101 means: A predetermination (pre-check of benefits) was already given.
What to do about denial code 101: Compare this to the earlier benefits estimate you received.
CO-101 vs PR-101 vs OA-101: what the prefix means
| Code on your EOB | What the prefix means | Who typically pays |
|---|---|---|
| CO-101 | Contractual obligation — the provider writes the amount off | Usually not the patient |
| PR-101 | Patient responsibility | The patient |
| OA-101 | Other adjustment | Often another payer or plan |
The prefix tells you who is expected to absorb the amount; the number (101) tells you why.
Related codes
CARC 100Payment was made to the patient or another party, not the provider.
CARC 102A major medical adjustment was applied.
CARC 95The provider billed in a way that doesn't follow the plan's rules.
CARC 104A managed-care withholding was applied to the payment.
Keep reviewing your bill
- Medical Bill vs EOB: What Is the Difference?
- How to Dispute a Medical Bill — Find Billing Errors Before You Pay
Frequently asked questions about Denial code 101
What does denial code 101 mean on my EOB?
A predetermination (pre-check of benefits) was already given.
What should I do about denial code 101?
Compare this to the earlier benefits estimate you received.
Found this code on your bill or EOB?
Upload the document — MD Bill Check decodes every code, checks the math line by line, and explains what's worth questioning.