What is the primary purpose of drug tests in relation to prescription or illegal drugs?

The primary purpose of drug tests, particularly in the context of prescription or illegal drugs, is to indicate the presence of one or more drugs in urine or blood. These tests are designed specifically to identify and quantify substances that may be legally prescribed or illicitly used, helping to determine if an individual has consumed drugs within a certain timeframe.

Such tests are essential in various settings, including medical evaluations, workplace drug screenings, legal investigations, and rehabilitation programs. By accurately detecting drugs in biological samples, healthcare providers can make informed decisions regarding a patient’s treatment, compliance with prescribed medications, or necessary interventions in case of substance abuse.

In contrast, measuring blood pressure, evaluating liver function, and determining metabolic rates serve different medical purposes and do not directly relate to the assessment of drug consumption. Each of those options targets specific health metrics rather than the presence of drugs in the system, reinforcing the distinction of drug tests as a tool for identifying drug use.