Dealing with the co45 denial code on your claims

If you've been looking in a stack of remittance advices recently, you've probably run into the co45 denial code more times compared to you'd like. It's one of all those things that pops upward constantly in the world of medical billing, and while it might look like a "rejection" in first glance, it's actually a really specific bit of communication from the insurance company. Honestly, if you're working in the billing office, you're going to see this particular code almost every single day, so it's worth obtaining comfortable with what it's looking to tell a person. ...

March 18, 2026 · 7 min · Terri Marius