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Drugs of abuse array i (blood semi-quantitative)

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Drugs of abuse array i (blood semi-quantitative) B A T (evidence investigatorâ„¢) 54 biochips EV3618 POA
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Intended Use

The Evidence Investigator Drugs of Abuse I Blood Semi-Quantitative Assays are in-vitro diagnostic tests for the semi-quantitative determination of the parent molecule and metabolites of drugs in human blood. They are competitive enzyme immunoassays run on the biochip array analyzer, Evidence Investigator.

This product is for forensic use only.

The Evidence Investigator Drugs of Abuse I Blood Semi-Quantitative Assays provide only a preliminary analytical test result and are for forensic use only. A more specific alternative chemical method must be used to obtain a confirmed analytical result. Gas Chromatography/mass spectrometry (GC/MS) is the preferred confirmatory method (1). Other chemical confirmation methods are available. Clinical consideration and professional judgement should be applied to any drug of abuse test result, particularly when preliminary positive results are used.

Clinical Significance

It is now accepted that drug misuse is a large and growing problem. Drug abuse has effects not only on the user but also on the whole of society. This can be in the form of crime; danger to other members of society and it can also cause an increased risk of the spread of transmittable diseases2. Blood drug testing can provide a tool for detecting users and for monitoring the compliance of subjects in recovery programs (3).

Principle

The Evidence Investigator analyzer performs simultaneous detection of multiple analytes from a single patient sample. The core technology is the Randox Biochip, a solid-state device containing an array of discrete test regions containing immobilized antibodies specific to different DOA compound classes. A competitive chemiluminescent immunoassay is employed for the DOA assays with the drug in the specimen and drug labeled with horseradish peroxidase (HRP) being in direct competition for the antibody binding sites. Increased levels of drug in a specimen will lead to reduced binding of drug labeled with HRP and thus a reduction in chemiluminescence being emitted. The light signal generated from each of the test regions on the biochip is detected using digital imaging technology and compared to that from a stored calibration curve. The concentration of analyte present in the sample is calculated from the calibration curve.

Several different immunoassay based multi-analyte arrays have been developed for use on Evidence Investigator. The DOA I WB SQ array will semi-quantitatively test for Amphetamine class (AMPH / MAMP), Barbiturates (BARB), Benzodiazepine class (BENZ 1 / BENZ 2), Cocaine (BZG), Methadone (MDONE), Opiates (OPIAT), Phencyclidine (PCP), and Cannabinoids (THC) simultaneously.

REFERENCES

1. Hawks RL. Analytical Methodology from Urine Testing for Drugs of Abuse, National Institute on Drug Abuse (NIDA), Research Monograph, 1986; 73:30-41

2. Galloway JH and March ID, Detection of drug misuse - an addictive challenge, J Clin Pathol, 1999; 52: 713-718

3. Glass L R, Ingalls S T, Schilling C L and Hoppel C L, Atypical Urinary Opiate Excretion Pattern, Journal of Analytical Toxicology, October 1997; 21:509-514.

 

Amphetamine Class Assay

Amphetamine (AMPH)

Methamphetamine (MAMP)

Intended Use

The Evidence Investigator amphetamine assays have been designed for use only on the Evidence Investigator analyzer for semi-quantitative detection of the amphetamine class of compounds in blood. This product is for forensic use only.

Clinical Significance

Amphetamines are synthetic drugs, which cause powerful central nervous system (CNS) stimulation resulting in euphoric effects similar to that of cocaine. They can also cause increased alertness, self-confidence and the ability to concentrate(1,2). They are potent sympathomimetic agents with a range of therapeutic applications for example; they can be used to treat mild depression, obesity, narcolepsy, and certain behavioural disorders in children (1,3). Isomeric forms of amphetamine and methamphetamine exist and the D-isomer (dextroamphetamine) is four times as potent as the L-isomer (2).

Abuse of amphetamines is a significant problem, although abuse of amphetamine is not widespread, methamphetamine abuse is and there has been much concern over 'ice', the solid form of methamphetamine (4). Amphetamine abusers can develop a tolerance for the drug, resulting in a psychological dependence and leading to drug abuse(3). Chronic abuse of amphetamine can lead to weight loss, hallucinations and paranoid psychosis, while acute overdose can cause agitation, hyperthermia, convulsions, coma and respiratory and/or cardiac failure (2). Large quantities of illegally synthesized amphetamines are manufactured. Many amphetamine analogues from the illicit market of the 1960s have been reintroduced and new analogues have been synthesized and marketed for their increased potency, altered pharmacological effects and difficulty of detection(1,4).

MDMA (Methylenedioxy-methamphetamine), MDA (Methylenedioxyamphetamine) and MDEA (Methylenedioxyethylamphetamine) are synthetically modified amphetamines. MDMA is one of the most common amphetamine analogues on the illicit market. It was previously used as an adjunct to psychotherapy but it was placed on the schedule of controlled substances in 1988. Despite this, it still remains very popular as a recreational drug. MDMA is metabolized to MDA, another drug known for its central stimulant properties(2,4).

Amphetamines are usually taken orally, intravenously or by insufflation(3). The half-life of amphetamines in humans is in the range 10 to 30 hours depending on the drug and the amount taken(5).

Evidence Investigator performs two amphetamine class assays, based on d-amphetamine and methamphetamine in the form of two discrete test regions (DTR) on the Drugs of Abuse (DOA) biochip. By performing both tests simultaneously the main amphetamines, metabolites and analogues can be detected giving a more accurate indication of recent drug use.

Principle

The Evidence Investigator Amphetamine Class Assay is a competitive chemiluminescent immunoassay for the detection of amphetamines in blood.

REFERENCES

1. Lee M-R, Yu S-C, Lin C-L and Yeh Y-Cia, Solid-phase extraction in Amphetamine and methamphetamine analysis of Urine, Journal of Analytical Toxicology, July/August 1997; 21: 278-282

2. Wild D. (ed), The Immunoassay Handbook, second edition, Nature Publishing Group, London, Basingstoke, New York, 2001; 783-788.

3. Hawks R L and Chiang C N, Urine Testing for Drugs of Abuse, NIDA Research Monograph, 1986; 73: 95-97

4. Cody J T, Detection of D, L-Amphetamine, D, L-Methamphetamine and illicit Amphetamine Analogs using Diagnostic Products Corporation's Amphetamine and Methamphetamine Radioimmunoassay, Journal of Analytical Toxicology, 1990; 14: 321-324.

5. Albertson T E, Derlet R W, Van Hoozen B E. Methamphetamine and the expanding complications of amphetamines. West J Med. April 1999;170(4):214-9.

 

Barbiturate (BARB) Assay

Intended Use

The Evidence Investigator Barbiturate assay has been designed for use only on the Evidence Investigator analyzer for semi-quantitative detection of barbiturates, in blood. This product is for forensic use only.

Clinical Significance

Barbiturates are a class of around 12 compounds derived from barbituric acid. They are central nervous system (CNS) depressants and they can be used as sedatives, hypnotics, anaesthetics and anti-epileptic drugs.

Barbiturates can be divided into three main groups according to their duration of action. The ultra-short-acting barbiturates are used clinically as anaesthetics whilst the long-acting barbiturates have anti-convulsing properties. The short-acting compounds are typically used as hypnotics (1, 2).

It is the short-acting barbiturates that are the most favoured by drug abusers due to their ability to reduce tension and produce a feeling of tranquillity without too much drowsiness. These include secobarbital, pentobarbital and amobarbital. The duration of action of short acting barbiturates is 3-6 hours(1, 2).

It is because of the barbiturate's sedative-hypnotic properties that they are frequently abused. Administration by abusers is nearly always by oral ingestion of tablets or capsules. An overdose of barbiturates can lead to a dramatic fall in blood pressure and body temperature, depressed respiration and coma. A continued use of barbiturates can lead to the development of tolerance and withdrawal can be dangerous for an addict(1,) (3).

The short-acting barbiturates are extensively metabolized by the liver to more pharmacologically inactive hydroxylated compounds(1). Typical of short-acting barbiturates, secobarbital has a half-life of 19-34 hours. Whereas long-acting barbiturate is much longer, e.g. phenobarbital has a half-life of about 24-140 hours(5).

Principle

The Evidence Investigator Barbiturate assay is a competitive chemiluminescent immunoassay for the detection of barbiturates in blood.

REFERENCES

1. Widdop B. (2001) Chapter 37, Drugs of Abuse. In: Wild D. (ed), (2001) The Immunoassay Handbook, Second edition, Nature Publishing Group, London, Basingstoke, New York, 781-816.

2. Simpson D., Braithwaite R.A., Jarvie D.R., Stewart M.J., Walker S., Watson I.W. and Widdop B. (1997) Screening for drugs of abuse (II): cannabinoids, lysergic acid diethylamide, buprenorphine, methadone, barbiturates, benzodiazepines and other drugs. Ann Clin Biochem, 34(5):460-510.

3. Kwong T.C., Chamberlain R.T., Frederick D.L., Kapur B. and SunshineI. (1988) Critical Issues in Urinalysis of Abused Substances: Report of the Substance-Abuse Testing Committee. Clin. Chem. 34(3):605-632.

4. Shen D. (1989) [Saliva phenobarbital concentration in epileptics] Zhonghua Shen Jing Jing Shen Ke Za Zhi. 22(6):369-370, 382.

5. Tokugawa K., Ueda K., Fujito H. and Kurokawa, T. (1986) Correlation between the saliva and free serum concentration of phenobarbital in epileptic children. Eur. J. Pediatr. 145(5):401-402

 

Benzodiazepine Assay

Benzodiazepine 1 (BENZ 1)

Benzodiazepine 2 (BENZ 2)

Intended Use

The Evidence Investigator Benzodiazepine test has been designed for use on the Evidence Investigator analyzer for semi-quantitative detection of benzodiazepine compounds, drugs with sedative and hypnotic effects, in blood. Evidence Investigator performs two Benzodiazepine assays based on oxazepam (Benzodiazepine Assay 1) and lorazepam (Benzodiazepine Assay 2). This product is for forensic use only.

Clinical Significance

The benzodiazepines are a group of over 20 structurally related central nervous system depressant drugs, each group varying considerably in their potency and clinical effects. The benzodiazepines are the most widely prescribed sedative/hypnotic drugs due to their wide range of uses (1,2,6). They are prescribed to treat anxiety, stress and insomnia. They are also used both as pre-medication and for induction of general anaesthesia. Most specific uses include the management of alcohol withdrawal, control of epileptic fits and relief of muscle spasms (3).

Benzodiazepines were first developed as hypnotic sedatives in the late 1960s and replaced the more problematic barbiturates, then associated with numerous overdoses (4). Benzodiazepines have the potential to elicit dependence and be abused, both in high doses and in low, therapeutic doses (5). They are taken because of their mood-altering properties and are known as 'downers' due to their ability to lessen the effects of opiate withdrawal and after-effects of ecstasy, amphetamine and LSD. However, chronic abuse leads to blurred vision, confusion, slow reflexes, slurred speech and hypotension(2). In spite of this, benzodiazepines are relatively safe drugs and have almost completely replaced the more toxic barbiturates.

Overdose and death are usually the result of the combination of benzodiazepine with other drugs or alcohol rather than taken alone (2,6).

Benzodiazepines are extensively metabolized by the liver by processes of N-dealkylation and hydroxylation followed by glucuronidation and only trace amounts of the parent compound are excreted. The most common metabolites are oxazepam and nordiazepam (2,5). Benzodiazepines are classified according to elimination half-life. Long-acting, intermediate and short-acting, and ultra-short acting benzoziazepines show half-lives exceeding 24 hours, between 5 and 24 hours, and less than 5 hours, respectively (7).

The highly addictive nature of benzodiazepines together with their wide availability and low-cost on the illicit drug market has created a population of people dependent on one or more benzodiazepines. There is therefore a need to monitor the uses and abuse of these drugs (3, 6).

By performing both Benzodiazepine Assays 1 and 2 simultaneously in the form of two discrete test regions (DTR) on the Drugs of Abuse biochip, the main benzodiazepines and their metabolites can be detected.

Principle

The Evidence Investigator Benzodiazepine Assays are competitive chemiluminescent immunoassays for the detection of benzodiazepines in blood.

REFERENCES

1. Beselt RC, Urine Drug Screening by Immunoassay: Interpretation of Results. In: Beselt RC, Advances in Analytical Toxicology, vol 1, chapter 5, 97-102.

2. Wild D. (ed), The Immunoassay Handbook, second edition, Nature Publishing Group, London, Basingstoke, New York, 2001; 790-793

3. Wolff K, Garretty D and Hay AWM, Micro-extraction of commonly abused benzodiazepines for urinary screening by liquid chromatography, Ann Clin Biochem, 1997; 34: 61-67

4. Garetty D J, Wolff K, Hay AWM and Raistrick D, Benzodiazepine misuse by drug addicts, 1997; 34: 68-73

5. Beck O, Lafolie P, Hjemdahl P, Borg S. Odelius G and Wirbing P, Detection of Benzodiazepine Intake in Therapeutic Doses by Immunoanalysis of Urine: Two Techniques Evaluated and Modified for Improved Performance, Clinical Chemistry, 1992; 38(2): 271-275

6. Simpson D, Braithwaite RA, Jarvie DR, Stward MJ, Walker S, Watson IW and Widdop B, Screening for drugs of abuse: II. Cannabinoids, lysergic acid diethylamide, buprenorphine, methadone, barbiturates, benzodiazepines and other drugs, Annals of Clinical Biochemistry, 1998; 34(5): 483-492

7. Greenblatt DJ, Shader RI, Divoll M, Harmatz JS. Benzodiazepines: a summary of pharmacokinetic properties. Br. J. Clin. Pharmacol. 1981; 11 Suppl 1:11S-16S.

 

Cocaine (BZG) Assay

Intended Use

The Evidence Investigator Cocaine metabolite assay is intended for use on the Evidence Investigator analyzer for semi-quantitative detection of cocaine in the form of the cocaine metabolite, benzoylecgonine, in blood. This product is for forensic use only.

Clinical Significance

Cocaine is a potent psychoactive substance, also known as 'coke' and 'snow' and it is extracted from the leaves of the South American shrub Erythroxylon coca (1, 2). The Coca leaves are traditionally chewed or sucked resulting in a slow absorption of the drug and hence a slow onset of action. Cocaine hydrochloride is a fine powder that may be insufflated (snorted), producing quick absorption and onset of effects. Intravenous use leads to a quick and powerful but brief effect. 'Crack' is a freebase form of cocaine which when smoked produces an immediate 'high', with a more intense euphoria and so has become the choice for many users (1, 3, 4). Cocaine causes severe psychological dependence. The abuse of cocaine dramatically increased in the middle and late 1980s and it continues to receive much attention by federal and local law enforcement (4).

Cocaine is administered in small doses. It stimulates the central nervous system (CNS) and the resulting effects include; increased alertness, euphoria, sense of confidence and physical strength that may encourage risk-taking behaviour (2, 3). It can also have local anaesthetic properties and cause an increased blood pressure, heart rate and body temperature. The euphoric effects show rapid onset, however within an hour they wear off leaving anxiety, fatigue and depression (3). Chronic abuse and overdose of cocaine can cause acute cocaine intoxication, which can lead to profound CNS stimulation, resulting in seizures and cardiac arrest (3, 4). Cocaine is also used in combination with other recreational drugs such as heroin, which contributes to many cocaine-associated deaths (5).

In the body, cocaine is rapidly converted to metabolites benzoylecgonine, by non-enzymatic loss of the methyl ester function, and ecgonine methyl ester, by enzymatic demethylation. Ecgonine can be formed by further hydrolysis of both these metabolites (6). The apparent half-life for cocaine is short; approximately 0.8 ± 0.2 hours, while the half-life of benzoylecgonine is 6 hours (7).

Principle

The Evidence Investigator Cocaine Metabolite Blood Semi-Quantitative Assay is a competitive chemiluminescent immunoassay for the detection of Benzoylecgonine in blood.

REFERENCES

1. Ray O, Ksir C. Stimulants. In: Ray O, Ksir C, eds. Drugs, Society and human behaviour, 5th ed. St. Louis: Mosby College Publishing, 1990: 112-39.

2. Beselt RC, Urine Drug Screening by Immunoassay: Interpretation of Results. In: Beselt RC, Advances in Analytical Toxicology, vol 1, chapter 5, 81-123.

3. Wild D. (ed), The Immunoassay Handbook, second edition, Nature Publishing Group, London, Basingstoke, New York, 2001; 796-799.

4. Eskridge KD and GuthrieSK, Clinical Issues Associated with Urine Testing of Substances of Abuse, Pharmacotherapy, 1997; 17(3): 497-510.

5. Wu A H B, Onigbinde T A, Johnson K G and Wimbish G H, Alcohol-Specific Cocaine Metabolites in Serum and Urine of Hospitalized Patients, Journal of Analytical Toxicology, March/April 1992; 16: 132-137.

6. Substance-Abuse Testing Committee, Critical issues in urinalysis of abused substances: report of the substance-abuse testing committee, Clin Chem, 1988; 34:605-32.

7. Couper FJ, Logan BK. Drugs and Human Performance Fact Sheets, Report from the National Highway Traffic Safety Administration, WashingtonDC. April 2004, page 20.

 

Methadone (MDONE) Assay

Intended Use

The Evidence Investigator methadone test has been designed for use only on the Evidence Investigator analyzer for semi-quantitative detection of methadone, a narcotic pain-relieving drug, in blood. This product is for forensic use only.

Clinical Significance

Methadone is a synthetic opioid analgesic, structurally related to Propoxyphene, and used clinically to decrease pain. Methadone was first synthesized as a substitute for morphine in Germany during the Second World War and has similar analgesic properties (1, 2).

Methadone is used in opioid withdrawal programs to replace the dependence of heroin, an illegal and short acting drug. Methadone being longer acting is taken to decrease the drug craving and the aim of the program is to help drug abusers to develop a lifestyle free of street drugs (4).

It is available in tablet and linctus form or as a solution for intramuscular injection. Methadone is prescribed on a wide scale and so there is danger of the drug finding its way into the street market of drug abusers (2, 5).

The side affects associated with methadone use can include physiological dependence, sedation, respiratory depression, respiratory failure and hypoxia. In cases of overdose this can cause coma, seizures, hypotension, and death (2-4).

Methadone is rapidly absorbed from the gastrointestinal tract and undergoes extensive metabolism in the liver. It is metabolized by mono- and di- N-demethylation to unstable metabolites that cyclise to give 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and 2-ethyl-5-methyl-3,3-diphenylpyrroline (EMDP) (1, 2, 6). These metabolites are excreted in the urine and bile. The half-life of (R,S)-methadone is 15-60 hours, and 10-40 hours for (R)-methadone (7). Unchanged methadone is the primary compound for detection by the Evidence Investigator Methadone assay.

Principle

The Evidence Investigator Methadone assay is a competitive chemiluminescent immunoassay for the detection of methadone in blood.

REFERENCES

1. Simpson D., Braithwaite R.A., Jarvie D.R., Stewart M.J., Walker S., Watson I.W., Widdop B. (1997) Screening for drugs of abuse (II): Cannabinoids, lysergic acid diethylamide, buprenorphine, methadone, barbiturates, benzodiazepines and other drugs. Ann. Clin. Biochem. 34(5):460-510.

2. Widdop B. Drugs of Abuse. In: Wild D. (ed). The immunoassay handbook, second edition, Nature Publishing Group, London, Basingstoke, New York, 2001; 781-816.

3. Kwong T.C., Chamberlain R.T., Frederick D.L., Kapur B. and SunshineI. (1988) Critical Issues in Urinalysis of Abused Substances: Report of the Substance-Abuse Testing Committee. Clin. Chem. 34(3): 605-632.

4. Anderson I.B., Kearney T.E. (2000) Use of methadone. West. J. Med. 172(1):43-6

5. Ling W., Wesson D.R. (1990) Drugs of abuse - opiates. West. J. Med. 152(5):565-72

6. Pohland A., Boaz H.E., Sullivan H.R. (1971) Synthesis and identification of metabolites resulting from the biotransformation of DL-methadone in man and in the rat. J. Med. Chem. 14(3):194-7.

7. Couper F.J., Logan B.K. Drugs and Human Performance Fact Sheets, Report from the National Highway Traffic Safety Administration, WashingtonDC. April 2004, page 55.

 

Opiates (OPIAT) Assay

Intended Use

The Evidence Investigator Opiates test has been designed for use only on the Evidence Investigator analyzer for the semi-quantitative detection of opiates in blood. This product is for forensic use only.

Clinical Significance

Morphine and codeine are opiates obtained from the opium poppy and are narcotic analgesic drugs. Morphine is one of the most effective and commonly used analgesics for the control of severe pain. Heroin and hydrocodone are semi-synthetic derivatives of morphine and codeine but are more correctly classified as opioids. These drugs have potent effects on the central nervous system including; analgesia, euphoria state, apathy, sedation and respiratory depression (1, 2, 3).

Illicit opiate use remains a major problem. Continued use can lead to tolerance and physical dependence. Heroin is the most commonly abused derivative and it is 2-3 times more potent as an analgesic than morphine. Being more lipid soluble, heroin crosses the blood-brain barrier more readily than morphine. Addicts can take heroin either by injection, nasal insufflation or smoking (4, 5, 6).

Opiate poisoning can result in individuals suffering respiratory depression, pinpoint pupils and often deep coma. Death from heroin overdose usually is a result of respiratory failure (3, 6, 7). The testing of patient samples has become increasingly necessary to monitor known or identify suspected drug abusers for opiates (8).

The plasma concentration of morphine declines rapidly within the first 10 minutes of intravenous administration due to tissue distribution and metabolism. Only 7% of an intravenously administered dose remains in the general circulation after 6 minutes. The elimination half-life of morphine is 177 minutes. Morphine is a common metabolite for several of the abused drugs in this category. For example, heroin is metabolized in humans to 6-mono-acetylmorphine (6-MAM) by chemical and enzymatic processes and it is then further metabolized rapidly to morphine and morphine conjugates (1). The Evidence Investigator Opiates assay is directed towards morphine.

Principle

The Evidence Investigator Opiates assay is a competitive chemiluminescent immunoassay for the detection of opiates in blood.

REFERENCES

1. Kwong T.C., Chamberlain R.T., Frederick D.L., Kapur B. and SunshineI. (1988) Critical issues in urinalysis of abused substances: report of the substance-abuse testing committee. Clin. Chem. 34(3):605-32

2. Joseph D.E. (Ed.) (2005) Drugs of Abuse. Published by the Drug Enforcement Administration, U.S. Department of Justice.

3. Ling W., Wesson D.R. (1990) Drugs of abuse - opiates. West. J. Med. 152(5):565-72

4. Kaiko R.F., Wallenstein S.L., Rogers A., Heidrich G. 3rd, Houde R.W. (1979) Relative analgesic potency of intramuscular heroin and morphine in cancer patients with postoperative pain: a preliminary report. NIDA Res. Monogr. 27:254-60.

5. Couper F.J., Logan B.K. Drugs and Human Performance Fact Sheets, Report from the National Highway Traffic Safety Administration, WashingtonDC. April 2004, page 74.

6. Widdop B. Drugs of Abuse. In: Wild D. (ed). The immunoassay handbook, second edition, Nature Publishing Group, London, Basingstoke, New York, 2001; 781-816.

7. Darke S, Zador D. (1996) Fatal Heroin 'Overdose': A Review. Addiction. 91(12):1765-1772.

8. Moore F.M.L., and Simpson D. (1989) Detection of opiates in urine: a cost-effective low risk immunoassay procedure, Med. Lab. Sci. 46(4):309-312.

 

Phencyclidine (PCP) Assay

Intended Use

The Evidence Investigator Phencyclidine test has been designed for use only on the Evidence Investigator analyzer for semi-quantitative detection of phencyclidine in blood. This product is for forensic use only.

Clinical Significance

Phencyclidine, 1-phenylcyclohexylpiperidine, is also known as PCP and 'angel dust' (1, 2). It is a synthetic drug developed in the 1950s as an anaesthetic and analgesic but was removed from the market due to its hallucinogenic properties and the unpredictable behavioural reactions, which occurred following anaesthesia(3, 4, 5).

PCP still has a legitimate use as a veterinary tranquilliser, however, in the 1960s PCP became a popular recreational drug leading to widespread street drug use and often resulting in incidences of overdose intoxication and death (1, 3). The toxic effects include; hypertension, seizures, coma and respiratory depression (5).

PCP is used by smoking with tobacco or marijuana, nasal insufflation ('snorting'), intravenous injection and oral ingestion (3, 5). It is a drug of abuse due to its euphoric and hallucinogenic effects. However, these effects can get quite erratic, with violent or bizarre behaviour often occurring (4). The effect of PCP may vary with dose, the user's settings and previous experiences with PCP (3).

PCP is hydroxylated and then glucuronidated and the metabolites are excreted renally. Up to 15% of PCP is eliminated unchanged in urine 6. The half-life of PCP ranges from 7-46 hours with the average being 21 hours (8).

The Evidence Investigator Phencyclidine Assay, tests for the parent molecule, 1-phenylcyclohexylpiperidine. Few substances cross-react with PCP in immunoassays 7.

Principle

The Evidence Investigator Phencyclidine Assay is a competitive chemiluminescent immunoassay for the detection of phencyclidine in blood.

REFERENCES

1. Gupta RC, Lu I, Oei G and Lundberg GD, Determination of Phencyclidine (PCP) in urine and illicit Street Drug Samples, Clinical Toxicology, 1995; 8(6): 611-621

2. Beselt RC, Urine Drug Screening by Immunoassay: Interpretation of Results. In: Beselt RC, Advances in Analytical toxicology, Biomedical Publications, California, 1984, vol 1, 81-123

3. Schneiders S, Kuffer P, Wennig R, Determination of lysergide (LSD) and phencyclidine in biosamples, Journal of Chromatography B, 1998; 713: 189-200

4. Eskridge KD, GuthrieSK, Clinical Issues associated with urine, Pharmacotherapy, 1997; 17(3): 506-507

5. Wild D. (ed), The Immunoassay Handbook, second edition, Nature Publishing Group, London, Basingstoke, New York, 2001; 808-810

6. Winger G, Hofmann FG, Woods JH, Hallucinogens: phencyclidine, LSD, and agents having similar effects. In: Winger G, Hofmann FG, Woods JH, eds. A Handbook on drug and alcohol abuse, the biomedical aspects. New York: OxfordUniversity Press, 1992; 98-116.

7. Walberg CB, Gupta RC, Quantification of phencyclidine in urine by enzyme immunoassay, J Anal Toxicol, 1982; 6: 97-9

8. Couper FJ, Logan BK. Drugs and Human Performance Fact Sheets, Report from the National Highway Traffic Safety Administration, WashingtonDC. April 2004, page 21.

 

Cannabinoids (THC) Assay

Intended Use

The Evidence Investigator Cannabinoids test has been designed for use only on the Evidence Investigator analyzer for semi-quantitative detection of cannabinoids in blood. This product is for forensic use only.

Clinical Significance

The Cannabinoids are a group of more than 60 C-21 compounds found in the plant, Cannabis sativa. The active ingredient in Cannabinoids is D-9-tetrahydrocannabinol (THC) (1). THC produces effects of euphoria, sedation and an altered time sense (1, 2, 3). Cannabinoids can be used in the treatment of various medical conditions, including glaucoma, asthma, multiple sclerosis and as an anti-emetic in patients undergoing cancer chemotherapy (3).

Marijuana is one of the most commonly used illegal substances in the United States and in many countries around the world (4). As a 'street' drug it is sold primarily as marijuana (flowering tops of the female plant) or hashish (the plant resin). Pure THC is almost never available on the 'black market' (1). The primary route of illicit consumption of cannabis is by smoking in cigarettes or pipes. It can also be ingested in cakes and confectionery and hashish oil (the most potent form) can be taken intravenously. An overdose of THC can cause hallucinations, coma and death (2,)(3).

The illicit use of marijuana as a recreational drug has led to the wide development of methods to detect if an individual has been using the drug (4). After inhalation the plasma concentration of THC rapidly declines with a half-life of 3.1 to 4.5 minutes. This is due to a combination of tissue absorption of the highly lipophilic THC and its metabolism. Thereafter, there is a much slower decline in plasma THC concentration with half-life between 19 and 36 hours. THC is rapidly metabolized to the principle inactive metabolite 11-nor-D(9)-THC-9-carboxylic acid (DCOOH-THC) and is conjugated with water-soluble glucuronic acid (1). Most of these water-soluble metabolites are excreted in the faeces and to a lesser extent in the urine (1). The large tissue store of THC and its gradual re-entry into the bloodstream results in THC metabolites being detected as much as 1-2 weeks after marijuana use depending on the route of administration, potency of THC and frequency of use (1). The most widely used test procedures employ immunoassay techniques to detect the presence of DCOOH-THC (3). The Evidence Investigator Cannabinoid Assay detects the two main THC metabolites: delta-9 and delta-8 analogues, 11-Nor-D(9)-THC-9-carboxylic acid and 11-Nor-D(8) -THC-9-carboxylic acid.

Principle

The Evidence Investigator Cannabinoid Assay is a competitive chemiluminescent immunoassay for the detection of cannabinoids in blood.

REFERENCES

1. Substance-Abuse Testing Committee. Critical issues in Urinalysis of abused substances: report on the substance-abuse testing committee. Clin Chem, 1988; 34: 605-32.

2. Schuckit M.A., Drug and Alcohol Abuse; A clinical guide to Diagnosis and Treatment, fifth edition, Kluwer Academic/Plenum Publishers, 2000; 11-12.

3. Widdop B. Drugs of Abuse. In: Wild D. (ed). The immunoassay handbook, second edition, Nature Publishing Group, London, Basingstoke, New York, 2001; 781-816.

4. Huestis M.A., Mitchell J.M. and Cone E.J., Detection Times of Marijuana Metabolites in Urine by Immunoassay and GC-MS, October 1995; 19: 443-449