What is a Modifier in Medical Billing?

Modifiers play an important role in modifying the medical codes for various medical situations. They are used when the physician decides to perform a procedure in a slightly different manner without changing its definition. Depending on the code for medical procedures or supplies, the physician is required to record the need for alteration of the procedure to get compensation for services. Thus the physician needs to add a modifier to the present medical code to reflect a change in the procedure.

The CPT book defines a Modifier as the “means to report or indicate that a service or procedure that has been performed has been altered by some specific circumstance but not changed in its definition or code.”

CPT Modifiers

A CPT modifier is a two digits numeric code. The CPT modifier is used to give additional information on medical procedures describing the need to use medical procedures, the site of the procedure, change in procedure, and the total number of surgeons performing the procedure. All of this information is represented in the format ‘CPT code-modifier’ and forwarded to the insurance payer. For example, 24115-52 is used to represent reduced services by the physician for “excision or curettage of bone cyst or benign tumor, humerus; with autograft (includes obtaining the graft)” due to minor complications.

Following are a few examples of CPT modifiers:

• Modifier 22 – Increased procedural services
• 23 – Unusual anesthesia
• 24 – Unrelated evaluation and management service by the same physician or other qualified health care professional during a postoperative period
• 25 – Significant, separately identifiable evaluation and management service by the same physician or other qualified health care professionals on the same day of the procedure or other service
• 52- Reduced services
• 53- Discontinued procedure
• 55- Postoperative management only
• 56- Preoperative management only
• 57- Decision for surgery
• 59- Distinct Procedural Services
• 99- Multiple modifiers

HCPCS Modifiers

An HCPCS modifier consists of two characters—one letter and one digit. HCPCS modifiers are grouped from A to Z coding category. The HCPCS modifier is used to give additional information on specific items used to deliver non-physician services. All of this information is represented in the format ‘HCPCS code-modifier’ and forwarded to the insurance payer. . For example, A0428-QN is used to represent “basic life support ambulance service, non-emergency transport, furnished by the provider of services.”

Following are a few examples of HCPCS modifiers:

• AA- Anesthesia services performed by anesthesiologists
• AD- Medical supervision by a physician, more than four concurrent anesthesia procedures
• AH- Clinical Psychologist (CP) Services. [Used when a medical group employs a CP and bills for the CP’s service]
• AJ- Clinical Social Worker (CSW). [Used when a medical group employs a CSW and bills for the CSW’s service]
• GW- Service not related to the hospice patient’s terminal condition
• GY- Item or service statutorily excluded or does not meet the definition of any Medicare benefit
• GZ- Item or service expected to be denied as not reasonable and necessary
• QN- Ambulance service furnished directly by a provider of services