A diagnostic assay is a procedure or test that is designed to detect, identify, or measure a specific substance or condition in the body. Synonyms for this term include diagnostic test, diagnostic technique, diagnostic procedure, and diagnostic screening. Additionally, biomarker assay, laboratory assay, clinical diagnostic assay, and medical assay can also be used interchangeably. These tests are essential in the medical field to make accurate and timely diagnoses of various conditions. In addition to laboratory assays, imaging techniques such as X-rays, CT scans and MRIs can also be used as diagnostic assays to identify internal medical abnormalities and conditions.