Diagnostic agent

Medical test
Intervention
X-ray of a hand. X-rays are a common medical test.
MeSH	D019937
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A medical test is a kind of medical procedure performed to detect, diagnose, or monitor diseases, disease processes, susceptibility, and determine a course of treatment. It is related to clinical chemistry and molecular diagnostics, and the procedures are typically performed in a medical laboratory.

Medical tests can be classified by what the test result will be used for, mainly including usage for diagnosis, screening or evaluation, as separately detailed below.

A diagnostic test is a procedure performed to confirm, or determine the presence of disease in an individual suspected of having the disease, usually following the report of symptoms, or based on the results of other medical tests. This includes posthumous diagnosis. Such tests include:

Screening refers to a medical test or series of tests used to detect or predict the presence of disease in individuals at risk for disease within a defined group, such as a population, family, or workforce. Screenings may be performed to monitor disease prevalence, manage epidemiology, aid in prevention, or strictly for statistical purposes.

Examples of screenings include measuring the level of TSH in the blood of a newborn infant as part of newborn screening for congenital hypothyroidism, checking for Lung cancer in non-smoking individuals who are exposed to second-hand smoke in an unregulated working environment, and Pap smear screening for prevention or early detection of cervical cancer.