Most Common Mistakes Made When Combining Medical Code Modifiers

Invalid modifier combinations are common reasons that cause medical claims to deny payment.  In addition to​ the accurate coding of treatment, medical claims must be billed in combination with codes for additional services performed in the office, the corresponding modifiers, if necessary, and ICD-9 or diagnosis codes.


Types of Invalid Modifier Combinations

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There are a number of ways that claims can be denied for invalid modifier combinations:

  • Modifier to modifier combinations: This includes the inappropriate billing of multiple modifiers. Not all modifiers can exist on the same line item or claim form.
  • Modifier to CPT/HCPCS code combinations: Not all modifiers are appropriate for all CPT/HCPCS codes.
  • Modifier to payer combinations: Not all payers utilize and recognize the same modifiers.

Modifiers 24 and 25

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Modifiers 24 and 25 are only valid when used in combination with Evaluation and Management Codes (E/M).

99201-05: New Patient Office Visit

99211-15: Established Patient Office Visit

99221-23: Initial Hospital Care for New or Established Patient

99231-23: Subsequent Hospital Care

99281-85: Emergency Department Visits

99241-45: Office Consultations

Modifier 24 (Unrelated) is used to identify E/M (Evaluation and Management) services provided on the same day of the surgery by the surgeon but is unrelated to the surgery.

Modifier 25 (Significant Separately Identifiable) is used to identify E/M (Evaluation and Management) services as separate from another service performed on the same day by the same provider.


Modifier 50

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The use of modifiers 26, LT, RT, and TC are considered as invalid combinations of modifiers when modifier 50 exists on the claim.

Modifier 50 is added to a procedure to indicate that a procedure is performed bilaterally.  The procedure should be billed as a single line item on the claim form with the modifier 50 and is typically reported with one unit of service (check with the payer to make sure, some payers may require the use of 2 units of service). 

Modifiers 26 and TC are only considered valid for procedures that have a professional component (26) or technical component (TC).

Modifiers LT and RT are only considered valid if a procedure is performed on one side of the body to indicate a unilateral procedure.  Use modifier 50 to indicate a bilateral procedure or RT/LT but not both.

Modifier 50 (Bilateral Procedures) is used to identify bilateral procedures during the same operative session.

Modifier 26 (Professional Component) is used to identify the professional component of a service performed by a physician or interpretation of the services performed by a physician.

Modifier LT (Left Side) is used to identify that the procedure is performed on the left side of the body.

Modifier RT (Right Side) is used to identify that the procedure is performed on the right side of the body.

Modifier TC (Technical Component) is used to identify the technical component of a service performed by a physician or interpretation of the services performed by a physician.


Modifier 59

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The use of modifier 76 is considered as an invalid combination when modifier 59 exists on the claim.

Modifier 59 is added to a procedure to distinguish a procedure as a different session, different surgery, different procedure, different site, different organ, separate incision, separate excision, or separate injury from the previously reported procedure that was performed on the same day by the same physician.

Use modifier 76 is the procedure is identical to the initial procedure performed.

Modifier 59 (Distinct Procedural Service) is used to identify services or procedures performed on the same day due to special circumstances that are not normally reported together.

Modifier 76 (Repeat Procedure) is used when the procedure is repeated by the same physician subsequent to the original service.

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