Medical testing equipment is a significant investment. Hospitals and clinics purchasing this equipment face substantial pressure to justify the expense by keeping the machines busy. This requires a steady stream of patients getting tested for various health conditions. Some clinics have responded to this pressure by advertising the tests directly to the public, without waiting for a physician to recommend the tests based on actual symptoms. The problem with this is that testing is not a no-risk proposition. Besides the worthless expense for many people, there are health risks to undergoing many medical tests. That risk is only acceptable when there are actual medical signs that the underlying problem may exist.
The problem of unnecessary testing, even when a doctor is consulted, is a long-standing one. Many of the tests ordered in hospitals today cannot be justified by medical research. Medical testing is big business and doctors have little incentive to keep medical costs low. Direct advertising from medical testing centers will likely make the problem worse.