Читать книгу An Introduction to Testing for Drugs of Abuse - William E. Schreiber - Страница 31

Urine is the best sample for determining whether someone has taken a drug within the recent past. It is an aqueous fluid that contains both drugs and their metabolites in a concentrated form. The window of detection varies from hours to a week or longer, depending on the specific drug and how much was taken.

Urine drug testing is ordered for a number of reasons.

 Confirm or rule out a suspected acute drug intoxication (eg, patient in the emergency room with symptoms of a drug ingestion).

 Discover use of illegal or prohibited drugs (eg, employment drug screening program).

 Monitor patients with a history of drug abuse (eg, drug rehabilitation program).

 Ensure compliance with drug prescriptions that might be diverted (eg, opioid screening in pain management clinics).

Urine is easy to collect and does not require special handling. Point‐of‐care screening tests can be performed directly on the sample with no additional preparation. Most compounds of interest are excreted in urine, so recent consumption of a drug is likely to be detected in this sample.

The main drawback of a urine sample is that it can be tampered with by the owner before analysis. The issue of specimen validity testing (SVT) is discussed later in this chapter.