In which situation would Modifier 90 not be applied?

Modifier 90 is specifically used to indicate that the laboratory procedures were performed by an outside laboratory and not by the treating physician or provider. This modifier is relevant in situations where the physician is sending specimens to an outside lab for analysis.

In the case of a physician performing a venipuncture, this action does not involve an outside laboratory performing the test itself. The physician is directly providing a service rather than using an external lab to analyze the sample. Therefore, in this context, Modifier 90 would not be appropriate to apply since it does not reflect the circumstances of the procedure performed by the physician.

On the other hand, Modifier 90 is applicable in situations where lab procedures are outsourced, such as when billing for laboratory tests that are conducted by an external lab or when no direct involvement of the treating physician in the analysis occurs. Thus, understanding the context of when and how services are rendered is key to determining the correct application of modifiers like 90.