Is sweat a suitable specimen for DUI testing?

Transcription

1 Is sweat a suitable specimen for DUI testing? Pascal K IN T Z and B ertrand L U D ES Institut de M edecine L egale 11 rue H um ann Strasbourg France IN T R O D U C T IO N It is generally accepted that chem ical testing o f biological fluids is the m ost objective m eans o f diagnosis o f drug use. T he presence o f a drug analyte in a biological specim en can be used as evidence o f recent exposure. The standard in drug testing is the im m unoassay screen, follow ed by the gas chrom atographic-m ass spectrom etric (G C /M S) confirm ation conducted on a urine sam ple. M ore recently, a variety o f body fluids other than urine, such as saliva (1.2) and sw eat (3,4) have been proposed to docum ent recent drug exposure. T he advantages o f saliva or sw eat over traditional m edia are obvious : collection is alm ost noninvasive, relatively easy to perform, and in forensic situations it m ay be achieved under close supervision o f law enforcem ent officiers to prevent adulteration or substitution o f the sam ples. In addition, it has been claim ed by som e authors that the concentrations o f m any drugs in saliva correlate w ell w ith blood concentrations, w hich suggests that quantitative m easurm ents in saliva m ay represent a technique o f value to determ ine the current degree o f exposure to a definite drug at the tim epoint o f sam pling. A m ong various possible applications in the field o f clinical or forensic toxicology, particular attention has been recently paid to the use o f saliva (5,6) or sw eat (7) fo r roadside testing o f subjects suspected o f im paired driving, as a consequence o f the increasing interest expressed by the authorities o f several countries tow ards the problem atics o f driving under the influence (D U I) o f psychoactive drugs. In relation w ith the French M inistry o f T ransportation, our L aboratory has developped a research program on the applicability o f sw eat testing for D U I control. C onsidering that a conditio sine qua non for such drug testings is that they can be organized in the sam e w ay as alcohol testings are (i.e. system atic controls directly carried out on the roadside by police

2 officers w ith m inim al scientific background, and obtention o f im m ediate results allow ing, if positive, the im m obilization o f the vehicle and the suspension o f the driver's license until eventual confirm ation tests), it has been especially em phasized that they should fulfill the follow ing requirem ents : 1) acceptability by the population, w hich com pels the sam pling procedure to be sim ple, fast and noninvasive, and 2) sim plicity and rapidity o f sam ple handling and analysis, w hich practically restricts the choice o f techniques to non-instrum ental im m unoassay. R ecently (8), the D rugw ipe (Securetec, V agen, G erm any), a non-instrum ental im m unoassay designated for use on site to obtain indications o f the presence o f illegal drugs (opiates, cocaine or cannabis) on surface w as used to docum ent drug fatal overdoses w hen used as a skin sw ab. By w iping the skin on the arm -pit, it w as dem onstrated that the opiate D rugw ipe tests m atched the results o f blood and urine exam inations in m ore than 80 % o f the cases. T his report describes the use o f the D rugw ipe opiates for sw eat testing after single oral adm inistration o f 60 m g o f codeine to 6 subjects. E X P E R IM E N T A L P resen tation o f the D rugw ipe T he D rugw ipe test kit is designed for use on site in order to obtain indications o f the presence o f illegal drugs on surface. B asically, all sm outh surfaces are suitable for testing. M oderately rough surfaces (suede, textiles, surface o f the body...) should be w iped carefully. T he D rugw ipe elem ents are presented unitary in a closed protective foil, stored at am biant tem perature. D ifferent tests are available for opiates, cocaine and cannabis. A ccording to the m anufacturer, a positive test result for the D rugw ipe "opiate" is obtained w ith 5 ng heroin, m orphine or codeine. T he test function is based on an im m unological detection m ethod. T he drug particles captured by the w iping section are transferred to the chrom atographic strip. D uring im m ersion in tap w ater the test absorbs an adequate volum e for chrom atography. T he w ater passes through the zone w ith binding specifically to various opiates. Excess conjugate is held back by a retention

3 zone w ith im m obilized m orphine deviate, so that only the conjugate laden w ith the w iped o ff drug particles reaches the detection field. D epending on the quantity w iped off, a coloration ranging from cream w hite to red w ill result (9). T he D rugw ipe opiates tests w ere offered by Securetec. S u b jects Six subjects, aged 25 to 36 years w ere recruited from laboratory personnel. A ll denied use o f codeine during the 3 previous m onths. T he w eek before enrollm ent, tw o urine tests w ere perform ed ; the results w ere negative. F our m ales and 2 fem ales participated in the protocol. They signed an inform ed consent agreem ent and w ere not paid for participation. S ixty m g o f codeine phosphate w ere orally adm inistered along w ith 100 m l w ater. Sw eat collection and analysis T he w iping section o f the D rugw ipe w as used to sw ab the forehead o f the subjects for 10 sec, after 1, 4, 9 and 24 hours codeine adm inistration. T he results w ere obtained as described previously for surfaces. A t the sam e tim e, for each period, a Pharm -C hek sw eat patch (Pharm C hem L aboratories, M enlo Park, C A ) w as applied to the outer portion o f the upper arm. C odeine w as then quantified in the patch by G C/M S according our procedure (10) and the m easured concentrations used as reference. R E SU L T S A ccording to the m anufacturer, it is not necessary for the read-out field o f the D rugw ipe to show an even coloration. T he coloration o f part sections o f the read-out field (on the edge, for exam ple) according to reference coloration also qualifies as a positive result. C oloration rem ains at least stable for 1 hour. R esults o f the D rugw ipe tests are obtained in less than 5 m in. T he analyses for sw eat are presented T able I. A s dem onstrated by the results, codeine can be easily detected in forehead sw eat using the D rugw ipe. By com parison w ith the sw eat patch, it seem s that the positive cuto ff for the D rugw ipe is close to ng/patch of codeine. Concentrations in the patch are in

4 the range o f previously reported values (10). It w as not possible to evidence codeine exposure w ith the D rugw ipe in the case o f subject 2. D ISC U SSIO N T he D rugw ipe m ethod m ay provide a rapid w ay to gather data about drug use w ithout the em barrassm ent often felt w hen obtaining urine sam ples. C learly, sw eat drug tests can reveal the presence o f a pharm acologically active drug in an individual at the tim e o f testing. R eference m ethods, like the sw eat patch technology, can provide valuable inform ation in diagnostics, treatm ent and forensic investigations o f individuals suspected o f drug abuse. W ith the exception o f one fem ale, all the subjects tested positive w ith the D rugw ipe in sw eat w ith a positive cut-o ff o f ng/patch. N o explanation w as found to docum ent the absence o f positivity observed w ith subject 2. She w as not under m edical treatm em nt and no drugs w ere detected after urinalysis. H ow ever, before using the D rugw ipe in routine for sw eat, standardization o f the collection o f the specim en m ust be established. At this tim e, the D rugw ipe w ill constitute an excellent non-instrum ental im m unoassay, that w ill be rapid, sensitive and applicable on noninvasive biological sam ples. T able 1: S w eat an alysis using the D rugw ipe and the sw eat patch for the 6 su b jects Tim e after codeine adm inistration (hours) Subjects W ipe Patch W ipe Patch W ipe Patch W ipe Patch F or the D rugw ipe : (+) : positive result, (-): negative result F or the patch : all concentrations in ng/patch -500-

5 R E F E R E N C E S 1. E.J. C one. S aliva testing for drugs o f abuse. A nn. N.Y. A cad. Sci. 694 : (1990) 2. W. Schram m, R.H. Sm ith, P.A. Craig, and D.A. Kidwell. Drugs o f abuse in saliva : a review. J. A nal. T oxicol. 16 : 1-9 (1992) 3. E.J. Cone, M.J. H illsgrove, A.J. Jenkins, R.M. K eenan, and W.D. Darwin. Sw eat testing for heroin, cocaine, and m etabolites. J. Anal. Toxicol. 18 : (1994) 4. P. K intz, A. T racqui, P. M angin and Y. Edel. Sw eat testing in opioid users w ith a sw eat patch. J. A nal. T o x icol. 20 : (1996) 5. O.R. Idow u, and B. Caddy. A review o f the use o f saliva in the forensic detection o f drugs and other chem icals. J. Forensic Sci. Soc 22 : (1982) 6. P.X. Iten. Fahren unter D rogen-oder M edikam enteneinflup. F orensische Interpretation und B egutachtung. Institute fur R echtsm edizin, Z urich, Sw itzerland, 1994, 233 p. 7. D.A. K idw ell, M.A. Blanco and F.P. Sm ith. Cocaine detection in a university population by hair and skin sw abs. Forensic Sci. Int. in press, H. Sachs and L. von M eyer. Sw eat testing for drugs using the D rugw ipe. In 34 th T IA FT m eeting abstracts. Interlaken, Sw itzerland, 1996, p D rugw ipe test. D rug detection kit. Securetec instructions. O ttobrunn bei M unchen, G erm any, A ugust P. K intz, A. T racqui, C. Jam ey, and P. M angin. D etection o f codeine and phenobarbital in sw eat collected w ith a sw eat patch. J. Anal. T o x ic o l. 20 : (1996)

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