Medical Billing Denial Codes and Solutions

Denial codes look cryptic, but they're a fixed vocabulary. Learn the handful that hit therapy practices most and you can resolve the majority of your denials without guesswork. Here are the common ones and their solutions.

The two code types: CARC and RARC

A CARC (Claim Adjustment Reason Code) gives the broad reason — like CO-16, 'claim lacks information.' A RARC (Remittance Advice Remark Code) adds the specific detail — like N290, 'missing/invalid rendering provider identifier.' Read them together: the CARC tells you the category, the RARC tells you the fix.

The codes therapists hit most

CO-16 (missing info — check the RARC), CO-97 (service bundled — may need a modifier), CO-197 (no authorization — but check parity rules), CO-29 (timely filing expired — appeal with proof), CO-109 (wrong payer — often a behavioral carve-out), CO-50 (not medically necessary — appeal with documentation), PR-1/2/3 (deductible/coinsurance/copay — patient responsibility, not a denial).

Solutions by category

Missing-info codes: supply the missing item and resubmit. Bundling codes: add the correct modifier if the service was distinct. Authorization codes: obtain retro-auth or appeal citing parity. Timely-filing: appeal with clearinghouse timestamps. Wrong-payer: verify the real behavioral-health payer and resubmit.

Decode any code instantly

We built a free denial code decoder that translates the common therapy denial codes into plain English with the exact fix for each. Bookmark it for the next cryptic code that lands.