Modifier 25 cuts a fine line in the medical billing world. Auditors tend to target medical billing claims with this modifier however CMS recently clarified again that they do indeed want this modifier used where appropriate in medical billing claims. The best rule for when to use modifier 25 is met when your physician provides a significant and separately identifiable E/M service on the same day as a procedure with a global period. If your services meet that requirement, you are free to use the modifier without worry in your medical billing claims. The CMS updated the usage language of the modifier in the release on August 20, 2006 and …