A Guide to the Use of CPT MODIFIERS

In order to describe the myriad number of different medical services, procedures, and factors accurately, CPT codes are divided into three Categories. Category I CPT codes describe medical, surgical, and diagnostic procedures (for instance, a routine checkup of low complexity is CPT code 99213). Category II CPT codes provide supplemental information to Category I CPT codes. The example used in Course 12 is the code for low-density lipoprotein cholesterol (CPT I code 80061) with a result of less than 100 mg of cholesterol per deciliter (CPT II code 3048F). This test and its result would be coded as 80061-3048F.

Category II CPT codes supply information that streamlines administrative work and tracks the performance of certain tests or procedures. These Category II codes, however, do not always provide important information about the specifics of a procedure, like on which side of the body a surgery took place, or whether a surgery was discontinued due to concern for patient safety.

See Examples of CPT Modifiers

In order to communicate this extremely detailed information in an efficient, standardized way, the AMA created CPT modifiers. CPT modifiers are two-character suffixes that healthcare providers or coders attach to a CPT code to give additional information about the procedure documented. CPT modifiers are always two characters in length. They may consist of two numbers from 21 to 99, two letters, or a mix (alphanumeric). These modifiers are appended to the initial CPT code by a hyphen.

Some examples of common CPT modifiers include:

• -53 (discontinued procedure)
• -59 (distinct procedural service)
• -79 (unrelated procedure or service performed by the same physician during the postoperative procedure).

Some common letter-based modifiers include:

• -LT (denotes a procedure on the left side of the body)
• -RT (denotes the right side of the body),
• -GC (identifies that a service has been performed by residents or students under the guidance of a teaching physician).

If you had to code a partial mastectomy of the left breast, you would use the CPT code 19302 for the procedure, with the modifier –LT to describe on which side of the body the procedure took place. Our code would read 19302-LT. If, however, the procedure had to be stopped because of a concern for the well-being of the patient, you would add another modifier: -53. The new code would read 19302-LT-53. Note that this is a simplified example, and that a procedure as complex as a mastectomy often has numerous additional codes).

Certain CPT modifiers are only used with a particular type of procedure or service. For instance, the modifier –LT used above is only valid when describing a procedure on an appendage or organ paired in the body, such as the lung, kidney, leg, or breast. The modifiers, -21, -24, -25, and -27 are only used for evaluation and management. Also, note that unlike CPT codes and ICD codes, CPT modifiers are not necessarily grouped into related procedures.

Functional vs. informational modifiers

There are a number of additional rules that govern the use of CPT modifiers. Coders must constantly look out for certain restrictions, formats, and guidelines, as a miscoded CPT modifier can result in a denied claim. Medical coders typically only use two CPT modifiers. While there is room for up to four modifiers on the CMS 1500 and UB-04 claim forms, the Center for Medicare and Medicaid Services (CMS) or other payers may not recognize modifiers after the first two. For this reason, coders should list first the modifiers that will affect reimbursement. These are often called functional or pricing modifiers, while modifiers that provide information about the procedure are known as informational. There are certain CPT modifiers, such as -22 (for unusual procedural services) and -52 (for reduced services), that affect reimbursement if documentation supports the use of this modifier.

Take, for example, the partial mastectomy of the left breast (code 19302-LT-53). If you were to swap out the -53 (discontinued procedure) with the functional modifier -52 (for reduced services), you would then code the whole procedure 19302-52-LT. Note that the functional modifier (-52) now comes before the informational modifier (-LT). If the informational modifier is listed first in a claim, an insurance company will deny that claim and return it to the healthcare provider.

Certain modifiers also have guidelines specific to them. The modifier -51, for multiple procedures, is one of the more commonly used CPT modifiers. In the instance of multiple procedures provided by the same specialist or healthcare provider, a coder would list the initial procedure’s CPT code, then append the modifier -51 to the end of the code for the additional procedure or procedures. Certain procedures, however, are listed in the CPT book as “-51 exempt,” and coders must be aware of this distinction.

Note that some modifiers can be used in conjunction with each other (like -23, unusual anesthesia, and -47, for anesthesia by surgeon). Others contradict one another and cannot be included in the same code For example, the modifier –LT (procedure on the left of two paired appendages or organs) cannot be coded with the modifier -50, which describes a bilateral procedure.