Add-on, reflexed, and bill-only tests are defined as follows:
Add-on test: A test that produces a result and is manually added to an original order. This type of test is added to an order when requested by a client, when recommended by the testing laboratory, or when the reflex process must be managed manually.
Reflexed test: A test that produces a result and is automatically performed based on the result of a previous test. The reflexes are determined by an algorithm or reflex action as described in the Test Catalog.
Bill-only test: A test code that does not produce a result and is used for billing purposes only, in order to carry a charge and CPT code.