Rational Use of Diagnostic Tests
diagnoses. In addition to confirming a disease state, diagnostic tests may also reveal
additional information as well about the severity of disease. They can yield useful prognostic
information and establish a baseline for treatment monitoring and disease progression.
Often, several diagnostic modalities can be used to seek a diagnosis in a symptomatic patient.
Each test has unique characteristics of which a clinician should be aware. For example, both
thoracic radiographs and computed tomography (CT) scan can be used to evaluate pulmonary
metastases. CT scan is the more sensitive modality due to superior contrast resolution and
diminished anatomic superimposition.[3,4] CT may be less specific though, since it detects
more lesions, many of which may be nonneoplastic. It would make sense to use CT scan as a
screening test. However, it is less readily available, more expensive, and requires general
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