Drugs of abuse array i (urine semi-quantitative)

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Intended Use

The Evidence Investigator Drugs of Abuse Array I Urine Semi-quantitative (DOA I URN SQ) Assays are in-vitro diagnostic tests for the semi-quantitative determination of the parent molecule and metabolites of drugs in human urine.

The Evidence Investigator DoA I URN SQ Kit is intended for forensic use only.

The Evidence Investigator DOA Array I Urine Semi-quantitative kit provides only a preliminary analytical test result. 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 diseases 2. Urine drug testing can provide a tool for detecting users and for monitoring the compliance of subjects in recovery programs (3).

Principle

Evidence Investigator Biochip Array Technology is used to perform 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 immobilised antibodies specific to different DOA compound classes. A competitive chemiluminescent immunoassay is employed for the DOA I URN SQ with the drug in the specimen and drug labelled 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 labelled with HRP and thus a reduction in the chemiluminescent signal 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.

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.

4. NCCLS, Urinalysis and Collection, Transportation, and Preservation of Urine Specimens: Approved Guidelines, December 1995: vol 15.

 

Phencyclidine (PCP) Assay

Intended Use

The Phencyclidine test has been designed for use only on the Evidence Investigator for the semi quantitative detection of phencyclidine in urine, using a cut-off concentration of 25 ng/mL. Results obtained can be utilised in screening for phencyclidine use or overdose.

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. PCP can be detected in urine for about one week, but this may increase to 2-4 weeks in long-term users (3,)(4).()

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 urine.

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.

 

Opiates (OPIAT) Assay

Intended Use

The Evidence Investigator Opiates test has been designed for use only on the Evidence Investigator for the semi quantitative detection of opiates in urine, using a cut-off concentration of 300 ng/mL. Results obtained can be utilised in the screening for opiate use or overdose.

Clinical Significance

Morphine and codeine are opiates. They are narcotic analgesic drugs, obtained from the opium poppy. Morphine is one of the most popular 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 are potent central nervous system depressants with effects including; the relief from pain, a dream-like euphoric state, narcosis and apathy (1, 2).

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 than morphine. With added acetyl groups it has better penetration across the blood-brain barrier than morphine. Addicts can take heroin either by intravenous injection, nasal insufflation ('snorting') or orally (2, 3).

Opiate poisoning can result in individuals suffering respiratory depression, pinpoint pupils and often deep coma. Overdose by intravenous injection can result in death within a few minutes(2). The testing of urine samples has become increasingly necessary to monitor known or identify suspected drug abusers for opiates (6).

In a single dose of morphine, about 10% is eliminated in the 72-hour urine as free morphine, and approximately 75% is present as morphine glucuronide. Morphine is a urinary metabolite common to several of the abused drugs in this category(1). For example, heroin is metabolised in humans to 6-mono-acetylmorphine (6-MAM) by chemical and enzymatic processes and it is then further metabolised rapidly to morphine and morphine conjugates (2, 4). 6-MAM is usually present in urine at less than 3% of the concentration of total urinary morphine (5) Very little free heroin is found in a urine sample after intravenous administration of a 10 mg dose. Approximately 8% of free heroin is found in urine and 67% of conjugated morphine after a four-day period (5). 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 urine.

REFERENCES

1. Beselt RC, Urine Drug Screening by Immunoassay: Interpretation of Results. In: Beselt RC, Advances in Analytical Toxicology, vol 1, chapter 5, 112-116.

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

5. 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.

6. Yeh SY, Gorodetzky CW and McQuinn RL, Urinary excretion of heroin and its metabolites in man. J. Pharm, Ex Ther. 1976; 196; 249-256.

 

Methadone (MDONE) Assay

Intended Use

The Evidence Investigator methadone test has been designed for use only on the Evidence Investigator for the semi quantitative detection of methadone, a narcotic pain-relieving drug, in urine using a cut-off concentration of 300 ng/mL. Results obtained can be utilised in screening for methadone use or abuse.

Clinical Significance

Methadone is a synthetic opioid analgesic, structurally related to Propoxyphene, and used clinically to decrease pain. Methadone was first synthesised as a substitute for morphine in Germany during the Second World War, due to its similar analgesic properties (2, 3).

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(1).

It is available in tablet form or as a solution for parenteral injection but it is most commonly prescribed in the form of a liquid mixture to avoid the 'rush' felt with intravenous drugs. 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.

The side affects associated with methadone use can include physiological dependence, sedation, respiratory depression and effects on the heart and on muscle. In cases of overdose this can cause stupor, hypotension, coma and circulatory collapse (1, 2).

Methadone is rapidly absorbed from the gastrointestinal tract and undergoes extensive metabolism in the liver. It is metabolised 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) (2, 4). Unchanged methadone is one of the main products excreted in urine and is the primary compound for detection by theEvidence Investigator Methadone assay.

Principle

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

REFERENCES

1. Schuckit, M.D. Drug and Alcohol Abuse: A Clinical Guide to Diagnosis and Treatment, fifth edition, Kluwer Academic/Plenum Publishers, New York, Boston, Dordrecht, London, Moscow, p11, 149, 162-163, 165, 327-329.

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

3. Simpson D, Braithwaite R A, Jarvie D R, Stewart M J, Waker S, Watson I W ad Widdop B, Screening for drugs of abuse (II): cannabinoids, lysergic acid diethylamide, buprenorphine, methodone, barbiturates, benzodiazepines and other drugs, Ann Clin Biochem, 1997; 34:475-480.

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

 

Barbiturate (BARB) Assay

Intended Use

The Evidence Investigator Barbiturate assay has been designed for use only on the Evidence Investigator for the semi quantitative detection of barbiturates, in urine using a cut-off of 200 ng/mL Phenobarbital. Results obtained can be utilised in screening for barbiturate use or abuse.

Clinical Significance

Barbiturates are a class of around 12 compounds derivatised 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-convulsant 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 of an addict can be dangerous (1,) (3).

The short-acting barbiturates are extensively metabolised by the liver to more pharmacologically inactive hydroxylated compounds. Only a small proportion of the parent compound (<0.2%) appears in the 24-hour urine. However, with large doses, there is usually sufficient of the parent compound present to give an adequate response and some of the hydroxylated metabolites will also cross-react in immunoassays(1).

Principle

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

REFERENCES

1. Wild D. (ed), The Immunoassay Handbook, second edition, Nature Publishing Group, London, Basingstoke, New York, 2001; 788-790.

2. Simpson D. Braithwaite R A. Jarvie D R. Stewart M J. Walker S. Watson I W and Widdop B. Screening for drugs of abuse (II): cannabinoids, lysergic acid diethylamide, buprenorphine, methadone, barbiturates, benzodiazepines and other drugs, Ann Clin Biochem, 1997; 34: 460-497.

3. 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.

 

Benzodiazepine Class Assay

Benzodiazepine 1 (BENZ1)

Benzodiazepine 2 (BENZ2)

Intended Use

The Evidence Investigator Benzodiazepine test has been designed for use on the Evidence Investigator for the semi quantitative detection of benzodiazepine compounds, drugs with sedative and hypnotic effects, in urine using a cut-off concentration of 200 ng/mL Results obtained can be utilised in screening for benzodiazepine use or abuse.

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 metabolised by the liver by processes of N-dealkylation and hydroxylation and only trace amounts of the parent compound appear in the urine. Many benzodiazepine metabolites are excreted in urine as glucuronide conjugates. The most common metabolites are oxazepam and nordiazepam(2,5).

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).

Evidence Investigator performs two benzodiazepine assays based on oxazepam (BENZ1) and lorazepam (BENZ2), in the form of two discrete test regions (DTR) on the DOA biochip. By performing both tests simultaneously the main benzodiazepines and their metabolites can be detected, giving a more accurate indication of recent drug use. Both results should be considered when identifying benzodiazepine preliminary positive samples.

Principle

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

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, Ann of Clin Biochem, 1998; 34(5): 483-492.

 

Amphetamine Class Assay

Amphetamine (AMPH)

Methamphetamine (MAMP)

Intended Use

The Evidence Investigator amphetamine assays have been designed for use only on the Evidence Investigator for the semi quantitative detection of the amphetamine class of compounds in urine using a cut-off concentration of 1000 ng/mL. Results obtained can be utilised in screening for amphetamine use or abuse.

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 synthesised amphetamines are manufactured. Many amphetamine analogues from the illicit market of the 1960s have been reintroduced and new analogues have been synthesised 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 metabolised to MDA, another drug known for its central stimulant properties. (2,4).

Amphetamines are usually taken orally, intravenously or by insufflation (3). Urinary elimination begins within 20 minutes of their administration. Depending on urinary pH, 30% of amphetamine dose is excreted unchanged in 24-hour urine, while 43% of methamphetamine is excreted unchanged with 7% excreted as amphetamine(5).

Evidence Investigator performs two amphetamine class assays, based on d-amphetamine (AMPH) and methamphetamine (MAMP) 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 urine.

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. 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.

 

Cannabinoids (THC) Assay

Intended Use

The Evidence Investigator Cannabinoids test has been designed for use only on the Evidence Investigator the semi quantitative detection of cannabinoids in urine, using a cut-off of 50 ng/mL. Results obtained can be utilised in screening for cannabinoid use or abuse.

Clinical Significance

The Cannabinoids are a group of more than 60 C-21 compounds found in the plant, Cannabis sativa (1). The active ingredient in Cannabinoids is D-9-tetrahydrocannabinol (THC). THC produces effects of euphoria, sedation and an altered time sense (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, 5).

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 hashish (flowering tops of the female plant) or marijuana (the plant resin). Pure THC is almost never available on the 'black market' (1, 3). 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). The time after marijuana use during which a positive urine test may result depends on the route of administration, potency of THC and frequency of use (1).

Only a small fraction of a dose of THC is excreted in the urine. THC is rapidly metabolised to the principle inactive metabolite 11-nor-D(9) -THC-9-carboxylic acid (DCOOH-THC). It is conjugated with water-soluble glucuronic acid and excreted in urine (3, 4). The most widely used test procedures employ immunoassay techniques to detect the presence of DCOOH-THC (3, 5). The Evidence Investigator Cannabinoid Assay detects the main THC metabolite: 11-Nor-D(9)-THC-9-carboxylic acid.

Principle

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

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

3. Wild D. (ed), The Immunoassay Handbook, second edition, Nature Publishing Group, London, Basingstoke, New York, 2001; 793-796.

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.

5. Huffman J W, Zhang X, Wu M, Joyner H H and Pennington W T, Synthesis of (±) - 11-Nor-9-carboxy-D(9) -tetrahydrocannabinol: New Synthetic Approaches to Cannabinoids, J. Org. Chem. (1991), 56; 1481-1489.

 

Cocaine Metabolite (BZG) Assay

Intended Use

The Evidence Investigator Cocaine metabolite test has been designed for use only on the Evidence Investigator for the semi-quantitative detection of cocaine in the form of the cocaine metabolite, benzoylecgonine, in urine at a cut-off concentration of 300 ng/mL. Results can be used to aid in screening for cocaine use or abuse.

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 by enzymatic and chemical processes. The two major urinary metabolites of cocaine are benzoylecgonine (BZG) and ecgonine methyl ester( 5). The plasma half-life of cocaine is only 0.7-1.5 hours and its urinary excretion is rapid (2). There is very little of the parent cocaine molecule excreted in urine (~1-9%). Benzoylecgonine is the primary urinary metabolite, accounting for 30-40% of the dose eliminated in the urine (2, 3, 6).

Principle

The Evidence Investigator Cocaine Metabolite Assay is a competitive chemiluminescent immunoassay for the detection of Benzoylecgonine in urine.

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. Zhang J Y and Folz R L, Cocaine Metabolism: Identification of Four Previously Unreported Cocaine Metabolites in Human Urine , Journal of Analytical Toxicology, July/August 1990; 14: 201-205.

 

Creatinine (CREAT) Assay

Intended Use

The Evidence Investigator creatinine assay has been designed for use only on the Evidence Investigator analyser for the semi quantitative assessment of creatinine in urine as a sample dilution marker using a cut-off concentration of 20 mg/dL.

Clinical Significance

Creatinine is present in all body secretions and is a by-product of muscle metabolism, formed by a spontaneous and irreversible conversion from creatine and creatine phosphate. The formation of creatinine is proportional to total muscle mass, and approximately to body weight. The production rate shows minimal daily variations, unless the muscle mass changes, with 2% of whole body creatine being transformed every 24 hours. (1)

Since creatinine is excreted at a relatively constant rate, measurement of urinary creatinine can indicate if the urinary concentration has been adjusted by in vivo or in vitro dilution. (3) Measurement of creatinine can be useful in drug screen urine analysis to detect false negative samples, as the ingestion of large volumes of fluid can dilute the concentration of a drug to a point below a level determined to be positive (2, 3). A creatinine value < 20 mg/dL should be used as a cut off, to evaluate the urine and the validity of the drug screening result (4). A level below this indicates that the sample may be falsely negative (4).

Principle

The Evidence Investigator Creatinine Assay is a competitive chemiluminescent immunoassay for the detection of creatinine in urine.

REFERENCES

1. Spenser K; Analytical reviews in clinical biochemistry: the estimation of creatinine; Annals of Clinical Biochemistry; 23: 1-25 (1986).

2. Lafolie P, Beck O, Blennow G, et al; Importance of creatinine analyses of urine when screening for abused drugs, Clinical Chemistry; 37/11: 1927-1931 (1991).

3. Needleman S. B., Porvaznik M, Ander D; Creatinine analysis in single collection urine specimens, Journal of Forensic Sciences; 37/4: 1125-1133 (1992).

4. Frazer A.D., Zamecnik J., Keravel J., McGrath L., Wells J.; Experience with urine drug testing by the Correctional Service of Canada, Forensic Science International; 121(1-2): 16-22 (2001).