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Home , Levomepromazine, Metaclazepam, Oxazolam

J Lab Med 2004;28(4):317–325 2004 by Walter de Gruyter • Berlin • New York 2004/03304

Drug Monitoring und Toxikologie Redaktion: V. W. Armstrong

Drug screening: Actual status, pitfalls and suggestions for improvement Drogenscreening: Gegenwa¨ rtiger Stand, Fehlermo¨ glichkeiten und Verbesserungsvorschla¨ge

Wolf R. Ku¨ lpmann* pretierbar. In Wirklichkeit mu¨ ssen viele Aspekte beru¨ ck- sichtigt werden, um einen aussagekra¨ ftigen Befund zu Klinische Chemie, Medizinische Hochschule Hannover, erhalten, z.B. Pra¨ analytik, Spezifita¨ t und Empfindlichkeit Hannover, Germany des Verfahrens oder Qualita¨ tssicherung. Obwohl die Abstract mechanisierten Meßverfahren naturgema¨ ß quantitative Ergebnisse liefern, wird aufgezeigt, daß es sich in der Immunoassays for drug screening are often regarded as Regel empfiehlt, qualitative Befunde zu erstellen. Die procedures which are easily performed and interpreted. Verfahren erlauben aber im Gegensatz zu den auch fu¨r But in fact, many aspects have to be considered to diese Zwecke verwendeten Teststreifen die Entschei- obtain a meaningful result. Among these are sampling, dungsgrenze (cut-off) der jeweiligen Fragestellung anzu- specificity and sensitivity of assays, and quality assess- passen, z.B. bei akuter Intoxikation, chronischem Abusus ment. Although the mechanised procedures yield quan- oder U¨ berwachung des Drogenentzugs. titative results, there are good reasons to generally report Ein schwerwiegender Nachteil von Immunoassays zum qualitative findings. The mechanised procedures allow Nachweis von Amphetamin und a¨ hnlichen Substanzen, the adjustment of the cut-off concentration to the clinical Barbituraten, Benzodiazepinen und Opiaten besteht dar- setting, e.g. in the case of acute intoxication, chronic in, daß eine starke Kreuzreaktivita¨ t des Antiko¨ rpers abuse or drug withdrawal, an important advantage as gegenu¨ ber pharmakologisch wenig wirksamen Verbin- compared to test strips. Procedures for the detection of dungen bestehen kann, wa¨ hrend stark wirksame Sub- , , or opiates stanzen der Gruppe, die in entsprechend niedriger are hampered by the fact that the analytical signal is in Konzentration vorliegen, wegen geringer Kreuzreaktivita¨t principle not related to the pharmacological effect of the ein vergleichsweise kleines analytisches Signal erzeugen contributing drug. A proposal for adjusting the analytical und so dem Nachweis entgehen ko¨ nnen. Es wird eine response to the pharmacodynamic action of a com- Empfehlung vorgelegt, wie empfindlich Pharmaka dieser pound is presented, as well as a list of drugs for which Gruppen unter Beru¨ cksichtigung ihrer Pharmakodynamik immunoassays are required. This may give guidance to nachweisbar sein sollten. Die entsprechende Aufstellung manufacturers for improving and developing assays. Pro- soll den Herstellern von Immunoassays Hinweise zur Ver- cedures for individual compounds should in general spe- besserung ihrer Verfahren geben. Weiter werden Sub- cifically detect the pertinent metabolite in urine as a proof stanzen aufgefu¨ hrt, fu¨ r die noch einfach durchfu¨ hrbare of drug uptake. Hydrolysis is mandatory in case of poor Nachweismo¨ glichkeiten beno¨ tigt werden. Nachweisver- cross-reactivity of the antibody with the excreted fahren fu¨ r einzelne Substanzen sollten in der Regel zum conjugates. Nachweis der Ko¨ rperpassage spezifisch nur den ent- sprechenden Metaboliten im Urin erfassen. Keywords: adulterants; confirmation analysis; immuno- Bei ungenu¨ gender Kreuzreaktivita¨ t der Antiko¨ rper assay; quality assessment; sensitivity; specificity; test gegenu¨ ber den u¨ berwiegend ausgeschiedenen Konju- strips; trend control. gaten muß dem Meßverfahren ein Hydrolyseschritt vorausgehen. Zusammenfassung Immunoassays zum Drogenscreening gelten vielfach als Schlu¨ sselwo¨ rter: Besta¨ tigungsanalyse; Empfindlichkeit; leicht durchfu¨ hrbar und ihre Ergebnisse als leicht inter- Immunoassay; Qualita¨ tssicherung; Spezifizita¨ t; Teststrei- fen; Verfa¨ lschungsstoffe; Verlaufskontrolle. *Correspondence: Prof. Dr. med. Wolf Ru¨ diger Ku¨ lpmann, Klinische Chemie, Medizinische Hochschule Hannover, Carl- Neuberg-Str. 1, 30625 Hannover, Germany Tel.: q49 511 532 6613 In this paper, drug screening is mainly confined to ana- Fax: q49 511 532 8614 lytical procedures used for the detection of drugs in urine 318 W.R. Ku¨ lpmann: Drug screening

Table 1 Characteristics of freshly voided urine.

Temperature: 32.0–37.78C temperature below 308C indicates an illegitimate sample Osmolality: 400–800 mmol/kg lower osmolality indicates a diluted sample Mass density: 1.003–1.030 kg/l lower mass density indicates a diluted sample Creatinine concentration: G9 mmol/l lower concentration indicates diluted urine, below 2.7 mmol/l dilution is obvious Nitrite: -125 mg/l a concentration exceeding 500 mg/l indicates contamination with adulterants Chromate: trace a concentration exceeding 100 mg/l indicates contamination with adulterants pH: 4–8 lower or higher values indicate contamination with acidic or alkaline solutions or substances by immunoassays. Immunoassays are commercially sample w2x. The solution contains another substance available for the following drugs in urine: which is not excreted in the urine to detect direct spoiling Amphetamines of urine with the test solution. Barbiturates It should be taken into account that addicts rather Benzodiazepines often suffer from hepatitis B or C as well as HIV, and Cannabinoids (THC) samples, especially blood or serum, should be handled Cocaine / Cocaine metabolite (Benzoylecgonin) cautiously to avoid infection. Lysergic acid diethylamide (LSD) / Methadone metabolite (EDDP) Opiates (total) and 6-Acetylmorphine Quality assessment Propoxyphene Immunoassays, which are run on mechanised analysers, yield by their very nature quantitative results (although a The reagents are certified for the use in urine. For the qualitative finding will be reported). Therefore, internal use in serum, dedicated reagent kits are available for tri- quality control should be performed according to the cyclic antidepressants, barbiturates and benzodiaze- guidelines in the same way w3x as for other measurable pines. The use of reagents for materials other than those quantities expressed on a ratio scale. The coefficient of declared is excluded from the manufacturer’s warranty variation (CV) for imprecision between series as an esti- and is at one’s own risk w1x. The risk may be low with mate of reproducibility should be below 7% for a sub- some assays of a certain manufacturer and high with his stance concentration near the cut-off concentration. In other assays or assays of other manufacturers. It can be practice, however, CVs up to 11% are observed. Official reduced if e.g. the serum is extracted and the dried criteria which need to be met have not been established extract is reconstituted with drug free urine. in Germany yet. Single measurements should not deviate Spot urine is appropriate for drug screening, but in from the mean more than 3-fold compared to the previ- some settings (examination of drug addicts, workplace, ously calculated CV. Knowledge of the precision at the car drivers, military personnel), adulteration has to be cut-off concentration is most important for the medical expected and a chain of custody must be set up. evaluation of the measurement results. Precision at high Through the internet, testees can obtain detailed advice concentrations may be poor because of a low steepness on how to ‘‘fool the bladder cops’’ and ‘‘how to beat drug of the calibration curve in this range. If control urine is tests’’. If adulteration is suspected, the laboratory should used containing the same drug as the calibrator of the investigate the freshly voided urine (Table 1). Dilution of assay, the mean should not deviate by more than 10% urine may be achieved by e.g. adding tap water or from the certified value (estimation of trueness). Appro- through excessive drinking. Readjustment of creatinine priate control material is available from the manufacturers to disguise dilution is tried by addition of creatine, which of the pertinent reagents or from companies specialised is easily available to body builders. Creatine at high con- in control materials w4x. centration is falsely taken for creatinine by enzymatic Test strips used for drug screening yield by their very procedures, but not by the Jaffe reaction. A general indi- nature qualitative results. Therefore, quality assessment cation for the presence of adulterants that interfere with is hampered and cannot be performed in the same the relevant method may be obtained by a sample check meticulous way as in quantitative measurements w5x.At assay (Microgenics, Passau). Dedicated procedures are best, control urine with the pertinent drug at a concen- commercially available for particular, often used adulter- tration exceeding the cut-off concentration is regularly ants. Recently, it was proposed that patients should be used to check whether the strips (still) yield valid findings. asked to drink a solution containing a marker substance, However, there is always some doubt whether the eval- which is excreted in the urine to detect an illegitimate uated strip is representative for those remaining. After a W.R. Ku¨ lpmann: Drug screening 319

while, the check has to be repeated to exclude deterior- noassays of different manufacturers may indeed have ation during storage. different cut-off values. The laboratory may change the External quality control schemes are offered in Ger- cut-off value with regard to the setting. The proposed many by the Deutsche Vereinte Gesellschaft fu¨ r Klinische cut-off value may be adequate in case of acute intoxi- Chemie und Laboratoriumsmedizin (DGKL), INSTAND or cation, but may be too high when monitoring a drug with- the Gesellschaft fu¨ r Toxikologische und Forensische drawal cure. The use of test strips is hampered by the Chemie (GTFCh). The ring trial of the DGKL takes place fact that the cut-off is fixed and cannot be changed twice a year. Immunoassays as well as chromatographic accordingly by the user. procedures (e.g. gas chromatography-mass spectrome- It has to be emphasised that for group assays, the cut- try) are evaluated simultaneously. The external quality off concentration is valid only for the drug used as cali- assessment for group assays is hampered by the fact brator (Table 2). Therefore, reporting the cut-off for a that the sensitivity of the different procedures for the indi- group assay may be misleading, as the clinician will vidual members of the group varies considerably and assume that it is valid for all members of the pertinent requires a dedicated evaluation. In the future, cut-off family of compounds. As the sensitivity of the different concentrations should be uniform for all procedures (see procedures for the individual members of a group varies below) to facilitate quality assessment and comparability considerably, the comparability of results is poor, espe- of results by different assays. cially at low and mid-range concentrations. Furthermore, At the moment, however, two group assays from dif- one has to bear in mind that cross-reactivity is usually ferent manufacturers may give contradictory results due only known for the mother compound, but not for its to different sensitivity for a relevant compound present in metabolites. If these metabolites are excreted predomi- the urine, not only in quality assessment schemes but nantly, the sensitivity of an assay which was set up for also in daily routine use. the mother compound may be questionable in practice. (Unfortunately, the metabolites are usually not readily available or only in very small amounts, thereby hamper- Specificity ing the clarification and impeding the production of ded- icated antibodies.) Specificity is usually quite good if only one compound at The same concentration of different members of a sub- rather high concentrations has to be detected, e.g. ben- stance group (e.g. benzodiazepines) evokes signals of zoylecgonine, cocaine, EDDP, methadone, phencycli- different intensity, because their cross-reactivities with dine, or propoxyphene. A procedure for the detection of the antibody are different. Furthermore, cross-reactivity LSD (Microgenics, Passau, Germany) will give false pos- changes with concentration (Table 2). Unfortunately, the itive results in the presence of ambroxol, bromhexin and cross-reactivity is not related to the presumably fentanyl, as will an assay for 6-acetylmor- of the compound. A less potent substance may produce phine in the presence of a high morphine concentration a high response whereas a very potent drug from the (Microgenics). Immunoassays for the detection of a same group may produce a small response; to make group of substances, e.g. amphetamines, barbiturates, matters worse, the effective concentration of the latter benzodiazepines or opiates, are less specific by their drug will be rather low. That is why a substance like flun- very nature, with the exception of immunoassays for itrazepam may escape detection, even though present in cannabinoids. effective concentration, whereas will usually be found even at sub-therapeutic concentrations. Table 3 presents a recommendation on how the manufacturers Detection limit and cut-off value should change the cross-reactivities of the assays to detect the substances according to their pharmacologi- The detection limit of the assays can be estimated by the cal effect and their frequency of use. measurement of drug free urine. However, a cut-off value rather than the detection limit is usually used to decide if a drug is present or absent w6x. The cut-off value is a Amphetamines decision limit to achieve an appropriate balance between truly positive and truly negative on the one hand and Assays should be appropriate to specifically detect only falsely positive and falsely negative on the other hand. and its most hazardous and frequently The lower the cut-off value, the more often a measure- abused derivatives. For practical reasons, other assays ment exceeding this limit will be falsely positive, mainly may be useful which allow screening also for less harmful due to interference. The higher the cut-off value, the members of the amphetamine group (e.g. , more often a false negative finding will be obtained and and others marked with ‘‘y’’ in Table 3). One a sample containing the drug will escape detection. The should remember that some drugs are metabolised to user should be aware that there may be different rec- yield amphetamines. Among these is selegiline, an MAO ommendations regarding cut-off values, especially for inhibiting drug used for treatment of M. Parkinson. It is amphetamines and cannabinoids, and that the immu- metabolised to methamphetamine. Benzphetamine 320 W.R. Ku¨ lpmann: Drug screening

Table 2 Cross-reactivity of immunoassays1).

Compound Concentration Cross-reactivity Concentration Cut-off concentration2) by weight (mg/l) (%) measured (mg/l) (mg/l) D-Amphetamine 300 100 300 300 MDE 300 46.7 140 y MDE 1000 35.0 350 q

Secobarbital 200 100 200 200 200 28.5 57 y Amobarbital 700 24.6 172 y 200 245.0 490 q

Nordiazepam 200 100.0 200 200 200 41.5 83 y Bromazepam 800 24.1 193 y

Morphine 200 100.0 200 200 Morphine-3b-Glucuronide 200 34.5 69 y Morphine-3b-Glucuronide 500 32.2 161 y Oxycodon 200 23.5 47 y Oxycodon 1000 10.5 105 y 1) Examples taken from Abbott (ADx) Manual, June 1994. 2) y, below cut-off concentration; q, exceeding cut-off concentration. yields methamphetamine, while prenylamine as well as It will provide strong evidence that cocaine has been fenethylline yield amphetamine. used. A procedure which is also reactive with cocaine itself may be misleading, because cocaine may be added to the urine after voiding; if the absence of metabolites Benzodiazepines is overlooked, the person will be wrongly blamed. How- ever, an assay specific for metabolites cannot be used Assays should cover those benzodiazepines that cur- for a preliminary identification of the mother compound rently are widely abused. The measurement procedures in suspect materials. must have improved the sensitivity to detect highly effec- tive drugs, e.g. , as well as the pertinent metabolites excreted in urine (e.g. 7-amino-flunitraze- Lysergic acid diethylamide (LSD) pam). As conjugates of the benzodiazepines usually escape detection, the assays should include hydrolysis. Antagonistic drugs such as should be non- Effective concentrations of LSD are rather low. Available reactive in the assays. assays are sufficiently sensitive but suffer from non- specificity. Cross-reactivity with other drugs must be eliminated, because confirmation analysis is difficult at this concentration level. At the moment, positive findings Cannabinoids will be most often due to interference by ambroxol, because LSD abuse is rather rare. Immunoassays for cannabinoids are commercially avail- able with different cut-off concentrations: 25 mg/l, 50 mg/l or 100 mg/l. A positive finding will usually be obtained only for the abuser himself, but not for a passive Methadone and methadone metabolites smoker. The assays are not suitable for the distinction between acute and chronic abuse. A positive finding by a specific assay for a methadone metabolite (e.g. EDDP) provides strong evidence that the patient has taken methadone. A specific procedure for Cocaine and cocaine metabolites methadone may yield misleading information. A minor portion of the ‘‘take home’’ dose may be added to the Usually, an assay which specifically measures a cocaine urine to produce a positive finding, whereas a major por- metabolite (e.g. benzoyl ecgonine) in urine is preferable. tion may have been retained and sold in the ‘‘scene’’. As W.R. Ku¨ lpmann: Drug screening 321

Table 3 Recommended cut-off concentrations for drug screening by immunoassays.

Amphetamines cut-off F 300 mg/l urine Amphetamine q 4-Hydroxyamphetamine (q) Phenmetrazine y BDB q MBDB q Phentermine y Bromamphetamine (q)MDAq Phenylethylamine y 4-Chloramphetamine (q)MDEq y y MDMA q PMA q DMBA y Mephentermine y PMMA q DOET (y) Methamphetamine q Propylhexedrine y DOM, (STP) (q) Methylphenidate y y Ephedrine y Norpseudoephedrine y Fenfluramin (y) Nylidrine y

Benzodiazepines cut-off F 200 mg/l urine (q) Desalkylflurazepam (q) q q Diazepam q q 7-Amino- q 50 (q) 50 (q) 7-Amino-Flunitrazepam q 50 Ethyloflazepate (q) 50 q 7-Amino- q 50 (q) (q) Bromazepam q Flumazenil yy Nitrazepam q 50 (q) 50 Flunitrazepam (q) 50 q (q) (q) (q) q (q) 50 q q (q) 50 (q) Clonazepam (q) 50 Hydroxy-Alprazolam q (q) (q) 3-Hydroxy-Bromazepam q q (q) 50 1-N-Hydroxyethylflurazepam (q) q (q) 50 Hydroxymidazolam q q (q) 50 q 50 q 50 (q) 50 (q)50 N-Desmethyl-Chlordiazepoxide q q

Assays should include hydrolysis of conjugates.

Buprenorphine metabolites cut-off F 20 mg/l urine

Cannabinoides cut-off F 25 mg/l urine (q) 11-OH-D-8-THC(q) 11-Nor-D-8-THC-9-carbonic acid (q) Cannabinol (q) 11-OH-D-9-THC (q) 11-Nor-D-9-THC-9-carbonic acidq 8-b-11-dihydroxy-D-9-THC (q)8-b-OH-D-9-THC (q)

Assays should include hydrolysis

Cocaine and metabolites cut-off F 300 mg/l urine Benzoylecgonin q Methylecgonin (q) Cocaine (y)

LSD and metabolites cut-off F 0.5 mg/l urine LSD (y) LSD-metabolite q Ambroxol yy Bromhexin yy

Methadone metabolites cut-off F 100 mg/l urine EDDP q EMDP (q) Methadone y 322 W.R. Ku¨ lpmann: Drug screening

Table 3 (continued)

Opiates and opioids cut-off F 300 mg/l urine Codeine q Hydromorphone q N-Norcodeine (q) (q) Ketobemidone (q) Norlevorphanol (q) Dextromoramid (q) Levorphanol (q) N-Normorphine (q) Dihydrocodeine q Morphine q Noroxymorphon (q) Dihydromorphine q Morphine-3-glucuronide q Oxycodone q Ethylmorphine q Naloxone yy Oxymorphon q Hydrocodone q Naltrexon yy Pholcodin (q)

Assays should include hydrolysis

6-Acetylmorphine cut-off F10 mg/l urine no cross-reactivity vs. other opiates

Tri- and antidepressants cut-offF100 mg/l urine or serum q q q q Levomepromazine q q q q q q q q q q IA, immunoasay q, detection by IA needed (q), detection by IA desirable, not mandatory (y), detection by IA not desirable y, not to be detected by IA yy, not at all to be detected by IA q 50, detection by IA required for concentrations F 50 mg/l, i.e. below general cut-off of the group F 200 mg/l BDB, Benzodioxazolylbutanamine DMBA, Dimethoxybromamphetamine (sDOB) DOB, 4-Bromo-2,5-dimethoxyamphetamine (sDMBA) DOET, 2,5-Dimethoxy-4-ethylamphetamine DOM, 2,5-Dimethoxy-4-methylamphetamine (sSTP) LSD, Lysergic acid diethylamide MBDM, Methylbenzodioxazolylbutanamine MDA, 3,4-Methylendioxyamphetamine MDE, 3,4-Methylendioxy-N-ethyl-amphetamine (s MDEA) MDEA, 3,4-Methylendioxy-N-ethyl-amphetamine (s MDE) MDMA, 3,4-Methylendioxy-N-ethyl-amphetamine PMA, p-Methoxyamphetamine (4-Methoxyamphetamine) PMMA, p-Methoxymethylamphetamine (4-Methoxy-N-methylamphetamine) STP, 2,5-Dimethoxy-4-methylamphetamine (sDOM) only L-methadone is active, it should be known whether in the presence of compounds marked ‘‘q’’, preferably L- or racemic methadone is applied and whether the also to substances marked ‘‘(q)’’ (Table 3). If hydrolysis cross-reactivity of the assay differs between the L- and is not included in the assay, glucuronides of the analytes D- forms. should also exert high cross-reactivity. Several assays may also give a positive result in urine from persons who have eaten pastry filled with poppy seeds (in US Jewish Opiates / opioids Purim cookies wHamantashenx). A positive finding in the opiate assay should be followed by an assay specific for The pertinent assays should detect opiates as well as 6-acetylmorphine. 6-acetylmorphine is indicative for dia- opioids (e.g. ketobemidone). However, as an antibody morphine (heroin) abuse, whereas a positive opiate assay reflects epitopes of the pertinent antigen, antibodies may be due to any compound with opiate structure. against morphine and its derivatives and antibodies Codeine itself may also exert a positive finding, even against the pertinent opioids have to be used in the though it is partly metabolised to yield morphine. Anti- assay. Actually, the procedures available detect only opi- dotes (naloxone, naltrexone) should not yield positive ates, but not opioids. They should yield positive findings findings. Because of increasing abuse of oxycodon in the W.R. Ku¨ lpmann: Drug screening 323

US, a special assay for this drug is under development, 4. Fentanyl as it is not detected with sufficient sensitivity by the 5. Tilidin assays now available. 6. Opioids used for the treatment of addicts (e.g. meth- 7. , adone, buprenorphine) should be monitored by special For some of these drugs w1, 7x, dedicated procedures assays highly specific for the urinary metabolites of these are reasonable. For others, one should include them into drugs. already existing groups by adding suitable antibodies. As it is not easy to produce a single antibody for this pur- pose, a mixture of several antibodies should be Tricyclic and tetracyclic antidepressants considered. Assays for serum and urine are commercially available. They should yield a positive finding for many drugs that differ considerably in structure. Mostly, their concentra- Hydrolysis tion is rather low. For these reasons, the assays are rath- er susceptible to interference. may yield Many drugs, e.g. benzodiazepines, cannabinoids, and a positive finding with some procedures even at sub- opiates are excreted predominantly in urine as conju- therapeutic concentrations. gates. Unfortunately, cross-reactivity of the antibodies in immunoassays is usually poor for these metabolites. Therefore, hydrolysis, e.g. by b-glucuronidase, is man- datory to release the mother compound in order to Barbiturates achieve the sensitivity claimed by the manufacturer. Some drawbacks of test strips stem from the fact that Barbiturates are not mentioned in Table 3. Their toxico- hydrolysis cannot easily be performed and the antibody logical role has dramatically decreased. On the whole, a does not react with the conjugates w5x. The importance cut-off concentration of 200 mg/l valid for all members of hydrolysis may be underestimated, because it is not of the group is considered adequate for most purposes. evident from quality assessment. Control urine usually It should be mentioned that , does not contain any conjugates and is therefore not and thiopental cannot be detected, because the amount mimicking samples from patients in this respect. excreted in urine is very small and most current immu- noassays exhibit a very low cross-reactivity with these compounds. Confirmation analysis

Methaqualone A positive finding with an immunoassay is but a suspi- cion of the presence of a particular drug (e.g. LSD) or of one or more members of the pertinent group of drugs. Methaqualone is rarely observed, as it is no longer pre- Therefore, a positive finding with an immunoassay must scribed. Therefore, routine screening for methaqualone is be re-examined by using another method principally dif- not recommended. ferent from immunoassays which is more specific and more sensitive, e.g. gas chromatography-mass spec- trometry. The presence of a drug can only be taken for Phencyclidine and propoxyphene certain if the confirmation analysis also yields a positive finding. In doubtful cases, even a negative finding of an These drugs were popular in the US, but not in Europe. immunoassay should be checked by another more sen- Most laboratories no longer investigate urine for these sitive and more specific method. In the future, drug substances in routine daily work. There may be an indi- screening could be performed primarily by liquid chro- cation for analyses if American military personnel are matography-tandem mass spectrometry instead of involved. immunoassays.

Other drugs Interpretation There are several drugs, for which appropriate screening Detectability depends on the time elapsed since appli- procedures, e.g. immunoassays, are urgently required: cation. Shortly after intake, the drug is not yet excreted 1. b-blocking agents in the urine, even though clinical symptoms may already 2. be evident. On the other hand, some drugs are rapidly 3. excreted and can only be detected within 24 hours. Oth- 324 W.R. Ku¨ lpmann: Drug screening

Table 4 Detectability of drugs after abuse ww9x, modifiedx.

Compound Urine Blood/Serum

Amphetamines (1–3) d1) up to 6 h Barbiturates - short acting 1 d hours, up to days - long acting (2–3) weeks Benzodiazepines Diazepam - therapeutic dosage 3 d hours, up to days - chronic dosage (4–6) weeks Cannabinoids - single use (24–36) h THC 5–12 h - moderate, chronic use 5 d - intensive, chronic use 20 d (-90 d) Cocaine (4–12) h not stable in blood Cocaine metabolite (Benzoylecgonin) (1–4) d Methadone 3 d very variable Opiates (2–3) d hours, up to days Phencyclidine, chronic use up to 30 d Propoxyphene (6–48) h 1) Increasing with decreasing pH of urine. THC, Tetrahydrocannabinol. ers, in case of chronic abuse, may be found in the urine Perspectives several weeks after the last dosage (e.g. cannabinoids). Table 4 gives an overview from observations in the According to the Federal Criminal Police Office (Bundes- ‘‘scene’’. Generally, findings from immunoassays are not kriminalamt), as published in the Report on Drugs and suitable to follow the time course of drug abuse w7x.In Addiction w8x of the Federal Government of Germany, fact, mechanised immunoassays yield quantitative persons who for the first time became known as abusers results, but the results depend on many variables, which took the following hazardous drugs (%): are not well known: Amphetamine 29% – Excretion may depend on pH of urine Cocaine 21% – Excretion depends on volume of urine (24 h urine? ‘‘Ecstasy’’ 20% Heroin 28% creatinine? osmolality?) LSD 1% – Sensitivity of the assay will be different for mother others 1% compound and metabolites – Sensitivity of the assay will be different for the different Among the less harmful drugs, cannabinoids and ben- members of the group zodiazepines are predominant. There are observations that the use of heroin, ecstasy, and hashish might be decreasing, whereas cocaine, The assay must have been calibrated using the perti- amphetamine and marihuana use might be increasing in nent drug, and other substances (e.g. metabolites) which Germany. exert cross-reactivity, must be absent. Therefore, the use Khat (Quat), which is mainly used by East-Africans, is of the assays to follow the time course is not encour- of little importance as well as from mush- aged; in the case of group assays, it may be strongly rooms. These drugs as well as , fentanyles misleading. If a testee no longer has access to diazepam (‘‘China white, Persian white’’), (DMT, DET, but now takes flunitrazepam, the time course will look DPT), prodines (derivates of , e.g. MPPP, promising with steadily decreasing results and the abuse PEPAOP), g-hydroxybutyrate (GHB, ‘‘liquid ecstasy’’), or will not be detected for several weeks. In the case of cannot yet be detected by immunoassays. The cannabinoid withdrawal, an increase in urinary excretion same holds true for , methyprylone, tilidine, may not be due to new THC abuse but may stem from clozapine and , as well as for the compounds excretion of metabolites with higher cross-reactivity than of betel (Areca catechu)orDatura stramonium and the one of their precursors. Generally, precision at con- organic volatiles for sniffing. These substances have to centrations exceeding the cut-off may be rather poor. To be detected by chromatographic methods. follow the time course, the pertinent drugs should pref- In 2002, 1513 persons in Germany died from drug erably be determined quantitatively in blood/serum by a abuse, which is 17.5% less than in 2001. In Germany, very specific method (e.g. chromatography with specific about 40 000 persons die every year from ethanol abuse, detection). 17 000 of them due to ethanol-induced liver cirrhosis. If W.R. Ku¨ lpmann: Drug screening 325

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