All of the following are true for a screeing test except-
Less accurate
Forms the basis for treatment
Test results are arbitrary
Less expensive
Screening tests do not form the basis for treatment as a specific diagnostic test will need to be performed to confirm the diagnosis suggested by a screening test in order to start a specific treatment.
For example, in HIV infection screening is done by ELISA. If the ELISA comes to be positive, western blot is done to confirm the diagnosis before starting treatment.