Editing Drug test (section)

===Urine drug screen===
[[File:Urine_drug_screen.jpg|thumb|Example of a device used to screen urine for drugs. There is no line present at the [[benzodiazepine]] area, indicating a positive screen for this class of drugs. Other drugs, and the negative control (labelled "C"), are negative.]]
Urine analysis is primarily used because of its low cost. Urine drug testing is one of the most common testing methods used. The enzyme-multiplied immune test is the most frequently used urinalysis. Complaints have been made about the relatively high rates of false positives using this test.<ref>{{Cite book|title = Drug use and abuse: A comprehensive introduction|last = Abadinsky|first = H.|publisher = Wadsworth Cengage Learning|year = 2014|isbn = 9781285070278|location = Belmont|pages = 163–165}}</ref>

Urine drug tests screen the urine for the presence of a parent drug or its metabolites. The level of drug or its metabolites is not predictive of when the drug was taken or how much the patient used.<ref>{{Citation |last1=Verstraete |first1=Alain G. |title=Clinical Drug Testing |year=2022 |url=http://www.ncbi.nlm.nih.gov/books/NBK557523/ |work=StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=32491455 |access-date=2022-10-21 |last2=Mukhdomi |first2=Taif |archive-date=July 5, 2024 |archive-url=https://web.archive.org/web/20240705030054/https://www.ncbi.nlm.nih.gov/books/NBK557523/ |url-status=live }}</ref>

Urine drug testing is an [[immunoassay]] based on the principle of competitive binding. Drugs which may be present in the urine specimen compete against their respective drug conjugate for binding sites on their specific antibody. During testing, a urine specimen migrates upward by capillary action. A drug, if present in the urine specimen below its cut-off concentration, will not saturate the binding sites of its specific antibody. The antibody will then react with the drug-protein conjugate and a visible colored line will show up in the test line region of the specific drug strip.<ref>{{Cite book |last1=Garrels |first1=Marti |url=https://books.google.com/books?id=LM9sBQAAQBAJ&dq=Urine+drug+testing+is+an+immunoassay+based+on+the+principle+of+competitive+binding.+Drugs+which+may+be+present+in+the+urine+specimen+compete+against+their+respective+drug+conjugate+for+binding+sites+on+their+specific+antibody.+During+testing%2C+a+urine+specimen+migrates+upward+by+capillary+action.&pg=PA289 |title=Laboratory and Diagnostic Testing in Ambulatory Care - E-Book: A Guide for Health Care Professionals |last2=Oatis |first2=Carol S. |date=2014-08-20 |publisher=Elsevier Health Sciences |isbn=978-0-323-29236-8 |language=en}}</ref>

A common misconception is that a drug test that is testing for a class of drugs, for example, [[opioids]], will detect all drugs of that class.  However, most opioid tests will not reliably detect [[oxycodone]], [[oxymorphone]], [[meperidine]], or [[fentanyl]].<ref>{{Cite journal|last1=Pesce|first1=Amadeo|last2=West|first2=Cameron|last3=Egan-City|first3=Kathy|last4=Strickland|first4=Jennifer|date=July 2012|title=Interpretation of Urine Drug Testing in Pain Patients|journal=Pain Medicine|language=en|volume=13|issue=7|pages=868–885|doi=10.1111/j.1526-4637.2012.01350.x|pmid=22494459|issn=1526-2375|doi-access=free}}</ref> Likewise, most [[benzodiazepine]] drug tests will not reliably detect [[lorazepam]].<ref>{{cite book |last1=Shaw |first1=Leslie M. |title=The Clinical Toxicology Laboratory: Contemporary Practice of Poisoning Evaluation |date=2001 |publisher=Amer. Assoc. for Clinical Chemistry |isbn=9781890883539 |page=216 |url=https://books.google.com/books?id=pXvFGqz44pYC&pg=PA216 |language=en}}</ref><ref>{{cite book |last1=Ries |first1=Richard K. |last2=Miller |first2=Shannon C. |last3=Fiellin |first3=David A. |title=Principles of Addiction Medicine |date=2009 |publisher=Lippincott Williams & Wilkins |isbn=9780781774772 |page=301 |url=https://books.google.com/books?id=j6GGBud8DXcC&pg=PA301 |language=en |access-date=May 27, 2020 |archive-date=January 12, 2023 |archive-url=https://web.archive.org/web/20230112235030/https://books.google.com/books?id=j6GGBud8DXcC&pg=PA301 |url-status=live }}</ref>  However, urine drug screens that test for a specific drug, rather than an entire class, are often available.

When an employer requests a drug test from an employee, or a physician requests a drug test from a patient, the employee or patient is typically instructed to go to a collection site or their home. The urine sample goes through a specified 'chain of custody' to ensure that it is not tampered with or invalidated through lab or employee error. The patient or employee's urine is collected at a remote location in a specially designed secure cup, sealed with tamper-resistant tape, and sent to a testing laboratory to be screened for drugs (typically the [[Substance Abuse and Mental Health Services Administration]] 5 panel). The first step at the testing site is to split the urine into two [[wikt:aliquot|aliquots]]. One aliquot is first screened for drugs using an analyzer that performs immunoassay as the initial screen. To ensure the specimen integrity and to detect possible adulterants, additional parameters are tested for.<ref>{{Cite web|url=https://sobercheck.co.nz/how-adulteration-works/|title=How adulteration works|date=October 11, 2021|access-date=October 22, 2021|archive-date=October 22, 2021|archive-url=https://web.archive.org/web/20211022034938/https://sobercheck.co.nz/how-adulteration-works/|url-status=live}}</ref> Some test the properties of normal urine, such as, [[Creatinine|urine creatinine]], pH, and [[specific gravity]]. Others are intended to catch substances added to the urine to alter the test result, such as, oxidants (including bleach),<ref>{{Cite journal|url=https://pubmed.ncbi.nlm.nih.gov/32924786/|pmid = 32924786|year = 2021|last1 = Aydoğdu|first1 = M.|last2 = Akgür|first2 = S. A.|title = Urine drug-testing tampering approaches: Turkish probationers|journal = Medicine, Science, and the Law|volume = 61|issue = 1|pages = 6–13|doi = 10.1177/0025802420956453|issn=0025-8024|s2cid = 221720183}}</ref> nitrites,<ref>{{Cite journal|url=https://pubmed.ncbi.nlm.nih.gov/30408836/|pmid = 30408836|year = 2019|last1 = Steuer|first1 = A. E.|last2 = Kamber|first2 = D.|last3 = Kraemer|first3 = T.|title = Evaluation of endogenous urinary biomarkers for indirect detection of urine adulteration attempts by five different chemical adulterants in mass spectrometry methods|journal = Drug Testing and Analysis|volume = 11|issue = 5|pages = 638–648|doi = 10.1002/dta.2539|s2cid = 53241111|access-date = October 22, 2021|archive-date = October 22, 2021|archive-url=https://web.archive.org/web/20211022033450/https://pubmed.ncbi.nlm.nih.gov/30408836/|url-status = live}}</ref> and gluteraldehyde.<ref>{{Cite journal|url=https://pubmed.ncbi.nlm.nih.gov/27645818/|pmid = 27645818|year = 2016|last1 = Fu|first1 = S.|title = Adulterants in Urine Drug Testing|journal = Advances in Clinical Chemistry|volume = 76|pages = 123–163|doi = 10.1016/bs.acc.2016.05.003|isbn = 9780128046876|access-date = October 22, 2021|archive-date = October 22, 2021|archive-url=https://web.archive.org/web/20211022033448/https://pubmed.ncbi.nlm.nih.gov/27645818/|url-status = live}}</ref> If the urine screen is positive then another aliquot of the sample is used to confirm the findings by [[gas chromatography]]—[[mass spectrometry]] (GC-MS) or [[LC/MS|liquid chromatography - mass spectrometry]] methodology. If requested by the physician or employer, certain drugs are screened for individually; these are generally drugs part of a chemical class that are, for one of many reasons, considered more habit-forming or of concern. For instance, [[oxycodone]] and [[diamorphine]] may be tested, both [[sedative]] [[analgesics]]. If such a test is not requested specifically, the more general test (in the preceding case, the test for opioids) will detect most of the drugs of a class, but the employer or physician will not have the benefit of the identity of the drug.

Employment-related test results are relayed to a medical review office (MRO) where a medical physician reviews the results. If the result of the screen is negative, the MRO informs the employer that the employee has no detectable drug in the urine, typically within 24 hours. However, if the test result of the immunoassay and GC-MS are non-negative and show a concentration level of parent drug or metabolite above the established limit, the MRO contacts the employee to determine if there is any legitimate reason—such as a medical treatment or prescription.<ref>{{cite web|title=Medical Review Officer Manual|url=http://workplace.samhsa.gov/DrugTesting/pdf/MRO_Manual_2010_100908.pdf|publisher=SAMSHA Gov|url-status=dead|archive-url=https://web.archive.org/web/20130215084325/http://workplace.samhsa.gov/DrugTesting/pdf/MRO_Manual_2010_100908.pdf|archive-date=February 15, 2013|df=mdy-all}}</ref>

On-site instant drug testing is a more cost-efficient method of effectively detecting substance use amongst employees, as well as in rehabilitation programs to monitor patient progress.<ref>{{Cite book |last=Treatment |first=Center for Substance Abuse |url=https://www.ncbi.nlm.nih.gov/books/NBK64092/ |title=Appendix B. Urine Collection and Testing Procedures and Alternative Methods for Monitoring Drug Use |date=2006 |publisher=Substance Abuse and Mental Health Services Administration (US) |language=en |access-date=October 21, 2022 |archive-date=October 22, 2022 |archive-url=https://web.archive.org/web/20221022212713/https://www.ncbi.nlm.nih.gov/books/NBK64092/ |url-status=live }}</ref> These instant tests can be used for both urine and saliva testing. Although the accuracy of such tests varies with the manufacturer, some kits have rates of accuracy correlating closely with laboratory test results.<ref>{{Cite web |url=https://www.confirmbiosciences.com/knowledge/blog/everything-need-know-instant-drug-tests/ |title=Article in ''Confirm Biosciences'' |access-date=September 2, 2017 |archive-date=January 25, 2021 |archive-url=https://web.archive.org/web/20210125035217/https://www.confirmbiosciences.com/knowledge/blog/everything-need-know-instant-drug-tests/ |url-status=dead }}</ref>