Getting the Most from Modifier 59, 25 and 91: A Guide for Coders

“If it isn’t coded, then it hasn’t been done.”

Correctly applying modifiers, though, isn’t always as easy as it seems. Many times providers inappropriately use modifiers, an action that inevitably can lead to claim denials.

“Modifiers are essential tools in the coding process,” says Laura Reeds, director of coding compliance at IASIS Healthcare in Franklin, Tenn. “They clarify how things should be paid … and further explain or qualify a CPT code.”

CPT modifiers (also called Level I modifiers) supplement the information or adjust care descriptions to provide extra details about a procedure or service provided by a physician. Code modifiers help further describe a procedure code without changing its definition.

Let’s take a look at 3 commonly misused modifiers, and see how they’ve been applied to different care situations.

Modifier 59

CPT Manual defines modifier 59 as a “Distinct Procedural Service.”

CMS says coders most often misuse modifier 59. Clinicians normally use modifier 59 to show that they performed two or more procedures during the same visit to different sites on the body.

Unfortunately, it was too often applied to prevent a service from being bundled or conjoined with another service on the same claim. Perhaps to prevent overuse or even abuse, CMS recently announced significant changes to modifier -59, essentially transforming this modifier into 4 more specific ‘X codes.’


A dermatologist does a Photo Dynamic Therapy session with a BLU-U machine on the face/scalp of a patient. Following the face/scalp session, the BLU-U was repositioned to treat extremities.

Coding examples:
96567-XS (formerly 96567–59)

The first code is the face/scalp performed on the patient. Then, modifier X code “XS” for “Separate Structure” is added to the second procedure, indicating a distinctly different procedure performed on a separate organ/structure.

Modifier 25

In Appendix A, the CPT 4 Manual defines modifier 25 as:

“Modifier 25 is a Significant, Separately Identifiable Evaluation and Management Service by the Same Physician on the Same Day of the Procedure or Other Service.”

Physicians can use this modifier to show that on the day they performed a procedure or service (identified by a CPT code), the patient’s condition required a significant, separately identifiable E/M service above and beyond the other service provided.

When Not to Use the Modifier 25:
Do not use a 25 modifier when billing for services performed during a postoperative period if related to the previous surgery.
Do not add modifier 25 if there is only an E/M service performed during the office visit.
Do not append modifier 25 to an E/M service when performing a minimal procedure on the same day unless you can support the level of service as significant, separately identifiable.


A patient visits the cardiologist for an appointment complaining of occasional chest discomfort during exercise. The patient has a history of hypertension and high cholesterol. After the physician completes an office visit, the doctor determines the patient needs a cardiovascular stress test that same day.

Coding example:
99214 – 25

The physician codes an E/M visit (99214) and he or she also codes for the cardiovascular stress test (93015). They add modifier 25 to the E/M visit to show that there was a separately identifiable E/M on the same day of a procedure.

Modifier 91

Modifier 91 indicates when the same provider performs repeat tests on the same day. In this scenario, the clinician obtains reportable test values with separate specimens taken at different times, and only when it is necessary to get multiple results in the course of treatment.  When billing for a repeat test, use modifier 91 with the appropriate procedure code.

When not to use modifier 91:
·       Rerun of a laboratory test to confirm results
·       Rerun due to testing problems with the specimen
·       Rerun due to testing problems with the equipment
·       When the procedure code describes a series of tests
·       For any reason when a normal, one-time result is required


A patient with high blood pressure who has been on a low-salt diet may receive a plasma renin activity (PRA) test (84244 Renin) in the morning in the supine position. Because physicians may use variations in PRA levels due to time of day and patient position to evaluate certain conditions such as hyperaldosteronism, they may order a repeat renin in the afternoon with the patient standing upright for a period of time.

Coding example:
84244 – 91

Report the second 84244 with modifier -91 to show that the lab performed two separate renin assays for the same patient on the same day.

For more information on these and other modifiers, see the CPT (Current Procedural Terminology) and HCPCS (HCFA Common Procedural Coding System) codebooks.

Xavier E. Martinez contributed to this post.

Outsourcing your medical billing to experts can reduce modifier misuse and confusion. See our In-House vs. Outsourced Medical Billing Revised: Pros and Cons post to learn if outsourcing is right for your practice.

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