Here are a few quick tips to help you make the most of CPT “add-on” codes:

  • Add-on codes describe procedures or services that are always provided “in addition to” other, related services or procedures. Add-on codes cannot stand alone as separately reportable services.
  • Add-on codes are identified throughout the CPT® manual by a “+,” and their descriptor will contain some variation of the phrase “report in addition to code for primary procedure.” You can find a complete list of add-on codes in Appendix D of the CPT® manual.
  • Add-on codes have no global period assigned. They are instead “included” in the global surgical fee for the primary procedure.
  • Add-on codes are “modifier 51 exempt,” and therefore are to be paid at full fee schedule value. Their assigned value accounts for the “additional” nature of the procedure.
  • It’s best practice to periodically check your explanation of benefits carefully for claims with add-on codes to be sure the payer is reimbursing you the entire fee schedule rate for the billed procedures or services. If you find a payer reducing the fees for your add-on codes, be sure to appeal the claims.