CMS-1500 Claim Form Practice Test 2026 - Free Practice Questions and Study Guide

The key idea is that the service date drives how you bill. CPT code changes within a year don’t automatically rewrite what was done. On a CMS-1500 claim, you should use the CPT code that was in effect on the date the service was performed. This keeps the claim accurate to what actually happened and aligns with how most payers review coding tied to the service date.

Because payers may have their own rules about how to handle code changes, you must check whether they accept retroactive changes or require a crosswalk to the new code. If they do, you’d adjust the claim accordingly and follow their submission guidance. That’s why it’s important to confirm payer acceptance of any changes and to update your internal payer rules to reflect those policies. Do not switch to the new code for a service that was performed when the old code was valid unless the payer specifically directs you to do so.

In short, bill with the code that matched the service date, and coordinate with the payer on any permitted changes and the resulting submission procedures.