The Differences Between Modifiers 51 and 59

Mary LeGrand, RN, MA, CCS-P, CPC

One of the most frequently asked question about modifiers is “When do I use modifier 51 and when do I use modifier 59?” This article differentiates the use of these modifiers when two or more procedures are performed on the same day.

About modifier 51
Modifier 51 (multiple procedures) is used to inform payers that two or more procedures are being reported on the same day. A claim form (CMS 1500) that has modifier 51 appended to a CPT code(s) tells the payer to apply the multiple procedure payment formula to the CPT code(s) linked to the modifier 51, assuming the payer accepts this modifier.

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