Which modifier indicates the use of CMS approved CLIA waived tests?

The correct choice for indicating the use of CMS approved CLIA waived tests is the modifier QW. This modifier is specifically designated for identifying tests that are waived under the Clinical Laboratory Improvement Amendments (CLIA). By appending the QW modifier to a specific test code, it signals to payers that the laboratory test meets the criteria for the waived tests, which are simpler and generally more reliable. These tests do not require the same level of regulatory oversight as more complex tests, thus facilitating their use in various clinical settings.

In contrast, other modifiers do not provide this specific indication. For instance, Modifier 90 is used to denote that a service was performed by a provider other than the billing provider; Modifier 91 indicates that a repeat laboratory test was performed on the same day; Modifier 92 is related to the use of a disposable laboratory test. None of these options communicate the status of tests as Class Waived under the CLIA regulations, making QW the most appropriate choice for acknowledging CMS approved waived testing.