The first examination is plain films of the affected area. In a substantial number of cases, these will effectively diagnose osteomyelitis and no further evaluation is required. If the plain films are negative and osteomyelitis is perceived to be significantly likely, the next examination is usually a three-phase nuclear medicine bone scan of the affected area. Most of the time this test is diagnostic. However, if there is a known history of significant DJD, past fracture, or previous infection at the site of current clinical concern, then an indium labeled WBC nuclear medicine study should be performed concurrently with the three-phase bone scan. The bone scan and the indium scan results are compared and utilized to evaluate for the presence of acute osteomyelitis superimposed on existing chronic changes. Please note that this same rationale also applies to the evaluation of a potentially infected joint prosthesis e.g. a THR, since the surgery will produce a positive bone scan and the indium study will more specifically address concurrent infection.