One or more medical and diagnostic clinics are present in Clayton. A diagnostic service is a comprehensive examination of the patient to arrive at the cause of his ailment. This is, in fact, the first step of any medical science. The process uses advanced medical equipment and services such as X-rays, electrocardiograms, echocardiograms, MRIs, PET scans and so on. A diagnotician is a professional who can read the test results to arrive at the correct diagnosis. The patient is then referred to the appropriate specialized medical care provider, who may or may not be part of that clinic. Diagnostic checks may be covered by insurance, but you would be wise to check with your provider in advance. Internal medicine, radiology and nuclear medicine are all used in diagnostics.