When reporting services, what is the significance of using modifier -90?

Using modifier -90 is significant because it specifically designates that a laboratory service was performed by an outside laboratory. This modifier is applied to items and services when the test or procedure was conducted by a lab that is not directly associated with the provider or facility billing for the service. By indicating the utilization of an external lab, it helps streamline the billing process and aids in clarifying the responsibilities of different parties in the provision of care.

Understanding the application of modifier -90 is essential in medical coding and billing, as it ensures that claims are processed correctly and accurately reflect the services rendered. In contrast, other modifiers might pertain to different aspects such as treatment continuity, secondary conditions, or modifications to diagnoses, which do not align with the specific function of modifier -90.