Information requested from the billing/rendering provider was not provided or was insufficient/incomplete

Why this happens on dental claims

• Records requests mailed to an old practice address or sitting unread in payer portal message queues
• Periodontal charting or radiographs sent, but missing the specific dates or views the reviewer requested
• Development letters with short response windows, often 30 to 45 days, that lapse during busy months

How to appeal CO-226

1. Obtain the original request: what was asked, when, and where it was sent
2. Assemble exactly what was requested, item by item, and label each enclosure against the request
3. Submit with a cover letter listing the enclosures and proof of any earlier response your office sent
4. Ask the payer to reopen the claim rather than requiring a formal appeal, which many will do once the information arrives
5. Confirm receipt and calendar a follow-up at two to three weeks

How to prevent it

• Assign one owner to payer correspondence and portal messages, with a 48-hour logging standard
• Keep current practice addresses on file with every payer so requests actually arrive