فحص العقاقير

For other uses, see Drug testing (disambiguation).
Drug test
التشخيص الطبي
MeSHD015813

فحص العقاقير Drug test هو تحليل سوائل الجسم لتحديد ما إذا كان شخص ما يستخدم عقاقير محظورة. وتستخدم مثل هذه الفحوصات على نطاق واسع في أماكن العمل، والقوات المسلحة، والقضايا الجنائية، وبرامج معالجة إدمان العقاقير. كما تستخدمها أيضًا بعض الاتحادات الرياضية.

تستخدم فحوصات العقاقير الحديثة، أساليب الكيمياء الحيوية الدقيقة والموثوقة. وبصورة عامة يتضمن الإجراء إرسال عينة بول إلى المختبر لإجراء فحص أولي يسمى المقياسة المناعية، وإذا كانت نتيجة الفحص موجبة، يستخدم فحص التأكيد المعروف باسم الفصل الكروماتوغرافي بالغاز (الاستشراب الغازي) وقياس الطيف الكتلي للتأكد من النتائج. وعادة لا يبلغ المختبر عن نتيجة الفحص الموجبة، ما لم يظهر كلا الفحصين وجود عقار محظور. بالإضافة إلى ذلك، تتم مراجعة نتائج الفحص الموجبة بوساطة طبيب لتحديد ما إذا كان للشخص المعني مبرر قانوني لاستخدام العقار.

منذ ثمانينيات القرن العشرين، أصبح إجراء فحص العقاقير للمستخدمين والمتقدمين للوظائف من الممارسات المعتادة في العديد من الصناعات. ويعتقد العديد من قادة العمل التجاري، أن الأشخاص الذين يستخدمون العقاقير المحظورة، يصبحون عمالة رديئة وقد يعرضون حياة زملائهم للخطر. ولكن بعض العاملين ينظرون لفحص العقاقير باعتباره انتهاكًا لخصوصياتهم وحقوقهم المدنية. ويبدي بعض الناس قلقهم بشأن مدى دقة الفحوصات.

وفي عام 1986م، أمرت حكومة الولايات المتحدة الأمريكية كل الوكالات الفدرالية باخضاع موظفيها لفحص استخدام العقاقير المحظورة. ومنذ ذلك الحين، أصدرت الحكومة قوانين تنص على ضرورة إجراء فحص العقاقير للموظفين في صناعة الطاقة النووية وشركات النقل، بما في ذلك شركات الخطوط الجوية والسكك الحديدية. كما تبنت أيضًا العديد من الولايات والوكالات المحلية برامج لإجراء فحص العقاقير.

قد يجري الأطباء في بعض الأحيان فحوصات العقاقير لمعرفة ما إذا كان المريض يتلقى الجرعة المناسبة من الدواء الموصوف له. بالإضافة إلى ذلك، قد يستخدم مصطلح فحص العقاقير للإشارة إلى الاختبارات التي تجريها الشركات المصنعة، لتحديد مدى فاعلية العقاقير التي يرغبون في تصنيعها وبيعها بصورة شرعية.

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الفترات التي ينجح فيها الكشف

The detection windows depend upon multiple factors: drug class, amount and frequency of use, metabolic rate, body mass, age, overall health, and urine pH. For ease of use, the detection times of metabolites have been incorporated into each parent drug. For example, heroin and cocaine can only be detected for a few hours after use, but their metabolites can be detected for several days in urine. The chart depicts the longer detection times of the metabolites.

Oral fluid or saliva testing results for the most part mimic that of blood. The only exceptions are THC (tetrahydrocannabinol) and benzodiazepines. Oral fluid will likely detect THC from ingestion up to a maximum period of 6–12 hours. This continues to cause difficulty in oral fluid detection of THC and benzodiazepines.[1]

Breath air for the most part mimics blood tests as well. Due to the very low levels of substances in the breath air, liquid chromatography—mass spectrometry has to be used to analyze the sample according to a recent publication wherein 12 analytes were investigated.

Rapid oral fluid products are not approved for use in workplace drug testing programs and are not FDA cleared. Using rapid oral fluid drug tests in the workplace is prohibited in only:[2]

The following chart gives approximate detection periods for each substance by test type.[3]

Approximate values for detection periods[4]
Substance Urine Hair Blood / Oral Fluid
Alcohol 6–24 hours[5] Note: Alcohol tests may measure ethyl glucuronide, which can stay in urine for up to 80 hours up to 90 days[6] 12 to 24 hours
Amphetamines (except methamphetamine) 1 to 4 days[7] up to 90 days 12 hours
Methamphetamine 5 days- up to a week [8] up to 90 days 1 to 3 days[8]
MDMA (Ecstasy) 3 to 5 days up to 90 days 3 to 4 days
Barbiturates (except phenobarbital) 1–4 days or 2–3 weeks up to 90 days 1 to 2 days
Phenobarbital 2 to 3 weeks[9] up to 90 days 4 to 7 days
Benzodiazepines Therapeutic use: up to 7 days. Chronic use (over one year): 4 to 6 weeks up to 90 days 6 to 48 hours
Cannabis Passive inhalation: up to 22 minutes**
Infrequent users: 7–10 Days
Heavy users: 30 to 100 days[10][11][12]		 up to 90 days[10] 2 to 3 days in blood, up to 2 weeks in blood of heavy users[10] However, it depends on whether actual THC or THC metabolites are being tested for, the latter having a much longer detection time than the former. THC (found in marijuana) may only be detectable in saliva/oral fluid for 2 to 24 hours in most cases, though in rare cases has been detected up to 28 days after consumption.[13]
Cocaine 2 to 5 days (with exceptions for heavy users who can test positive up to 4/6 weeks, and individuals with certain kidney disorders) up to 90 days 2–10 days, heavy users or individuals with previous substance use 6/8 weeks
Codeine 2 to 3 days up to 90 days 1 to 4 days
Cotinine (a breakdown product of nicotine) 2 to 4 days up to 90 days 2 to 4 days
Morphine 2 to 4 days up to 90 days 1 to 3 days
Tricyclic antidepressants (TCA's) 7 to 10 days Undetectable[14] Detectable but dose relationship not established.
LSD 1–4 days (including metabolites) up to 4 days[بحاجة لمصدر] 2 to 4 days
Methadone 7 to 10 days up to 90 days 24 hours
Steroids 3 to 30 days
PCP 3 to 7 days for single use; up to 30 days in chronic users[15] up to 90 days 1 to 3 days[15]


الأنواع

كشف العقاقير في البول

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.[16]

Breath test

مقال رئيسي: Breathalyzer
Breath test being used on a volunteer.

Breath test is a widespread method for quickly determining alcohol intoxication. A breath test measures the alcohol concentration in the body by a deep-lung breath. There are different instruments used for measuring the alcohol content of an individual though their breath. Breathalyzer is a widely known instrument which was developed in 1954 and contained chemicals unlike other breath-testing instruments.[17] More modernly used instruments are the infrared light-absorption devices and fuel cell detectors, these two testers are microprocessor controlled meaning the operator only has to press the start button.

To get accurate readings on a breath-testing device the individual must blow for approximately 6 seconds and need to contain roughly 1.1 to 1.5 liters of breath. For a breath-test to result accurately and truly an operator must take steps such as avoiding measuring “mouth alcohol” which is a result from regurgitation, belching, or recent intake of an alcoholic beverage.[18] To avoid measuring “mouth alcohol” the operator must not allow the individual that's taking the test to consume any materials for at least fifteen minutes before the breath test. When pulled over for a driving violation if an individual in the United States refuses to take a breath test that individual's driver's license can be suspended for a 6 to 12 months time period.

اختبار الشَعر

مقال رئيسي: تحليل الشعر

Hair analysis to detect addictive substances has been used by court systems in the United States, United Kingdom, Canada, and other countries worldwide. In the United States, hair testing has been accepted in court cases as forensic evidence following the Frye Rule, the Federal Rules of Evidence, and the Daubert Rule. As such, hair testing results are legally and scientifically recognized as admissible evidence. [19]

Although some lower courts may have accepted hair test evidence, there is no controlling judicial ruling in either the federal or any state system declaring any type of hair test as reliable.

Hair testing is now recognized in both the UK and US judicial systems. There are guidelines for hair testing that have been published by the Society of Hair Testing (a private company in France) that specify the markers to be tested for and the cutoff concentrations that need to be tested. Addictive substances that can be detected include Cannabis, Cocaine, Amphetamines and drugs new to the UK such as Mephedrone.

الكحول

In contrast to other drugs consumed, alcohol is deposited directly in the hair. For this reason the investigation procedure looks for direct products of ethanol metabolism. The main part of alcohol is oxidized in the human body. This means it is released as water and carbon dioxide. One part of the alcohol reacts with fatty acids to produce esters. The sum of the concentrations of four of these fatty acid ethyl esters (FAEEs: ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate) are used as indicators of the alcohol consumption. The amounts found in hair are measured in nanograms (one nanogram equals only one billionth of a gram), however with the benefit of modern technology, it is possible to detect such small amounts. In the detection of ethyl glucuronide, or EtG, testing can detect amounts in picograms (one picogram equals 0.001 nanograms).


Commonly tested substances

Anabolic steroids

Anabolic steroids are used to enhance performance in sports and as they are prohibited in most high-level competitions drug testing is used extensively in order to enforce this prohibition. This is particularly so in individual (rather than team) sports such as athletics and cycling.

Methodologies

Before testing samples, the tamper-evident seal is checked for integrity. If it appears to have been tampered with or damaged, the laboratory rejects the sample and does not test it.

Next, the sample must be made testable. Urine and oral fluid can be used "as is" for some tests, but other tests require the drugs to be extracted from urine. Strands of hair, patches, and blood must be prepared before testing. Hair is washed in order to eliminate second-hand sources of drugs on the surface of the hair, then the keratin is broken down using enzymes. Blood plasma may need to be separated by centrifuge from blood cells prior to testing. Sweat patches are opened and the sweat collection component is removed and soaked in a solvent to dissolve any drugs present.

انظر أيضاً

المصادر

الموسوعة المعرفية الشاملة

المراجع

  1. ^ U.S. Department of Transportation: National Highway Traffic Safety Administration (DOT HS 810 704). Pilot Test of New Roadside Survey Methodology for Impaired Driving. January, 2007.
  2. ^ "Drug Testing - State by State Legal Status" (PDF). Alere Toxicology. Archived from the original (PDF) on January 25, 2014. Retrieved 2013-02-21.
  3. ^ "Drugs of Abuse Reference Guide," Pinnacle BioLabs, Retrieved online April 11, 2007.
  4. ^ "Heroin Test - Heroin Drug Test - Testing Blood - Urine Tests". TheGoodDrugsGuide. Retrieved مايو 11, 2016.
  5. ^ Erowid Alcohol Vault : Drug Testing. Erowid.org. Retrieved on August 7, 2011.
  6. ^ "Hair Alcohol Testing (EtG)". Psychemedics.com. Retrieved on June 23, 2016.
  7. ^ Erowid Amphetamine Vault : Drug Testing. Erowid.org. Retrieved on September 5, 2013.
  8. ^ أ ب Erowid Methamphetamine Vault : Drug Testing. Erowid.org. Retrieved on September 5, 2013.
  9. ^ Erowid Barbiturates Vault : Drug Testing. Erowid.org. Retrieved on August 7, 2011.
  10. ^ أ ب ت Erowid Cannabis (Marijuana) Vault : Drug Testing. Erowid.org (2010-02-28). Retrieved on August 7, 2011.
  11. ^ Marijuana Detection Time Shorter Than Previously Assumed. norml.org (2006-02-23). Retrieved on March 13, 2012.
  12. ^ Susan Squibb (مارس 9, 2016). "How long does weed stay in your system?". The Cannabist. Archived from the original on مارس 11, 2016. Retrieved مايو 25, 2016.
  13. ^ Lee, Dayong (2013). "Current Knowledge on Cannabinoids in Oral Fluid". Drug Testing and Analysis. 6 (1–2): 88–111. doi:10.1002/dta.1514. PMC 4532432. PMID 23983217.
  14. ^ "2D6O - Clinical: Cytochrome P450 2D6 Genotype, Saliva". mayomedicallaboratories.com.
  15. ^ أ ب Erowid PCP Vault : Drug Testing. Erowid.org (2009-11-03). Retrieved on August 7, 2011.
  16. ^ Abadinsky, H. (2014). Drug use and abuse: A comprehensive introduction. Belmont: Wadsworth Cengage Learning. pp. 163–165. ISBN 9781285070278.
  17. ^ Saferstein, R. (2013). Forensic science: From the crime scene to the crime lab. Upper Saddle River: Pearson Education Inc. pp. 295–300. ISBN 978-0131391871.
  18. ^ Saferstein, R. (2013). Forensic science: From the crime scene to the crime lab. Upper Saddle River: Pearson Education. pp. 295–303. ISBN 978-0131391871.
  19. ^ Huestis, M. A. (1996). "Judicial acceptance of hair tests for substances of abuse in the United States courts: scientific, forensic, and ethical aspects". Therapeutic Drug Monitoring. 18 (4): 456–459. doi:10.1097/00007691-199608000-00025. ISSN 0163-4356. PMID 8857568.


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