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4 results on '"lažno negativni rezultati"'

1. Effect of urine adulterants on commercial drug abuse screening test strip results

Author

Rajšić Ivana, Javorac Dragana, Tatović Simona, Repić Aleksandra, Đukić-Ćosić Danijela, Đorđević Snežana, Lukić Vera, and Bulat Zorica

Subjects
false negative, household chemicals, immunochromatographic assay, lemon juice, urit 11g, vinegar, imunokromatografski test, kućne kemikalije, lažno negativni rezultati, limunski sok, ocat, Toxicology. Poisons, RA1190-1270
Abstract

Immunochromatographic strips for urine drug screening tests (UDSTs) are common and very suitable for drug abuse monitoring, but are also highly susceptible to adulterants kept in the household, which can significantly alter test results. The aim of this study was to see how some of these common adulterants affect UDST results in practice and whether they can be detected by sample validity tests with pH and URIT 11G test strips. To this end we added household chemicals (acids, alkalis, oxidizing agents, surfactants, and miscellaneous substances) to urine samples positive for amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), tetrahydrocannabinol, heroin, cocaine, or benzodiazepines (diazepam or alprazolam) and tested them with one-component immunochromatographic UDST strips. The UDST for cocaine resisted adulteration the most, while the cannabis test produced the most false negative results. The most potent adulterant that barely changed the physiological properties of urine specimens and therefore escaped adulteration detection was vinegar. Besides lemon juice, it produced the most false negative test results. In conclusion, some urine adulterants, such as vinegar, could pass urine specimen validity test and remain undetected by laboratory testing. Our findings raise concern about this issue of preventing urine tampering and call for better control at sampling, privacy concerns notwithstanding, and better sample validity tests.

Published
2020
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2. Effect of urine adulterants on commercial drug abuse screening test strip results

Author

Rajšić, Ivana and Rajšić, Ivana

Abstract

Immunochromatographic strips for urine drug screening tests (UDSTs) are common and very suitable for drug abuse monitoring, but are also highly susceptible to adulterants kept in the household, which can significantly alter test results. The aim of this study was to see how some of these common adulterants affect UDST results in practice and whether they can be detected by sample validity tests with pH and URIT 11G test strips. To this end we added household chemicals (acids, alkalis, oxidizing agents, surfactants, and miscellaneous substances) to urine samples positive for amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), tetrahydrocannabinol, heroin, cocaine, or benzodiazepines (diazepam or alprazolam) and tested them with one-component immunochromatographic UDST strips. The UDST for cocaine resisted adulteration the most, while the cannabis test produced the most false negative results. The most potent adulterant that barely changed the physiological properties of urine specimens and therefore escaped adulteration detection was vinegar. Besides lemon juice, it produced the most false negative test results. In conclusion, some urine adulterants, such as vinegar, could pass urine specimen validity test and remain undetected by laboratory testing. Our findings raise concern about this issue of preventing urine tampering and call for better control at sampling, privacy concerns notwithstanding, and better sample validity tests., Preliminarna analiza prisutnosti psihoaktivnih tvari u mokraći pomoću imunokromatografskih testnih traka (UDST) našla je primjenu u mnogim područjima. Iako vrlo prikladne u kontroli zloporabe droga, testne su trake iznimno osjetljive na sredstva za patvorenje (adulterante) kao što su kućne kemikalije, što može značajno promijeniti rezultate testa. Cilj ovoga istraživanja bio je ispitati potencijal uobičajeno korištenih adulteranata kada je riječ o utjecaju na rezultate probira na prisutnost psihoaktivnih tvari u mokraći uporabom UDST-a. Ispitivane kemikalije (kiseline, lužine, oksidirajuća sredstva, površinski aktivne tvari i druge) dodane su uzorcima urina u kojima je, tekućinskom kromatografijom – masenom spektrometrijom (LC-MS) prethodno potvrđena prisutnost amfetamina, 3,4-metilendioksimetamfetaina (MDMA), tetrahidrokanabinola, heroina i kokaina benzodiazepina (diazepam ili alprazolam). U ispitivanju su korištene jednokomponentne imunokromatografske testne trake. Manipulacija uzorcima urina provjeravala se pomoću pH traka, kao i biokemijskih testnih traka za semikvantitativno određivanje koncentracija endogenih tvari i specifične težine uzoraka urina pomoću testnih traka URIT 11G. Rezultati ovoga ispitivanja pokazali su da je test za detekciju kokaina u urinu najmanje osjetljiv na utjecaj ispitivanih adulteranata, a test za detekciju kanabinoida najosjetljiviji, posebice u pogledu lažno negativnih rezultata. Najsnažniji adulterant koji je utjecao na rezultate testa a nije promijenio fiziološke parametre urina je alkoholni ocat. Osim soka od limuna, alkoholni ocat dodan u urin proizveo je najveći broj negativnih ishoda testiranja. Može se zaključiti da značajan broj adulteranata utječe na rezultate testa i da je moguće da neki od njih, poput alkoholnoga octa, mogu proći neopaženo pri kontroli valjanosti uzorka. Ovi nalazi upozoravaju na važnost strogo kontroliranog okruženja za uzorkovanje urina kako bi se spriječile manipulacije.

Published
2020

3. 18F-FLUORIDEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY/ COMPUTED TOMOGRAPHY IMAGING: ARTIFACTS AND PITFALLS.

Author

MIHAILOVIĆ, Jasna, MATOVINA, Emil, and NIKOLETIĆ, Katarina

Subjects
*FLUORODEOXYGLUCOSE F18, *POSITRON emission tomography, *COMPUTED tomography, *MEDICAL artifacts, *BIOMARKERS, *IMAGING of cancer
Abstract

18F-fluorodeoxyglucose, being a radiolabeled glucose analogue, is a marker of glucose metabolism indicator. Since glucose uptake is increased in malignant tumors, its major application is in oncology. However, an increased 18F- fluorodeoxyglucose uptake is found in various benign tumors, granulomatous diseases, tuberculosis, inflammation, infection. A healing process may be interpreted as a false positive finding. In contrast, some types of renal cell cancers and lymphomas, neuroendocrine tumors, colonic mucinous adenocarcinomata, hepatocellular carcinomas, prostate cancer, and carcinoid tumors have low 18F-fluorodeoxyglucose avidity which may give a misleading false negative result. In addition, an increased 18F-fluorodeoxyglucose uptake in the bone marrow may be seen in oncologycal patients following various types of therapy. Besides the advantages of hybrid positron emission tomography-computed tomography imaging, this dual-modality scanning may produce their own specific artifacts due to different causes, such as metallic implants, respiratory motion, contrast medium and truncation. Proper patient preparation is required to minimize the potential artifactual uptake patterns that make reporting difficult. It is important to learn about proper quality control, imaging and reconstruction and to be familiar with potential artifacts and pitfalls for the accurate interpretation of 18F-fluorodeoxyglucose positron emission tomography-computed tomography. [ABSTRACT FROM AUTHOR]

Published
2015
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4. Effect of urine adulterants on commercial drug abuse screening test strip results

Author

Ivana Rajšić, Danijela Đukić-Ćosić, Simona Tatović, Zorica Bulat, Vera Lukić, Snežana Đorđević, Aleksandra Repić, and Dragana Javorac

Subjects
Male, Test validity, Urine, Toxicology, 01 natural sciences, munokromatografski test, kućne kemikalije, 0302 clinical medicine, false negative, household chemicals, immunochromatographic assay, lemon juice, URIT 11G, vinegar, Household chemicals, 030212 general & internal medicine, Reagent Strips, Adulterant, Aged, 80 and over, Traditional medicine, biology, MDMA, Middle Aged, 3. Good health, Substance abuse, Substance Abuse Detection, Alprazolam, Female, Original Article, Drug Contamination, medicine.drug, Adult, 010402 general chemistry, 03 medical and health sciences, ocat, medicine, Humans, lažno negativni rezultati, Aged, business.industry, Illicit Drugs, Public Health, Environmental and Occupational Health, medicine.disease, biology.organism_classification, 0104 chemical sciences, imunokromatografski test, limunski sok, Cannabis, business
Abstract

Immunochromatographic strips for urine drug screening tests (UDSTs) are common and very suitable for drug abuse monitoring, but are also highly susceptible to adulterants kept in the household, which can significantly alter test results. The aim of this study was to see how some of these common adulterants affect UDST results in practice and whether they can be detected by sample validity tests with pH and URIT 11G test strips. To this end we added household chemicals (acids, alkalis, oxidizing agents, surfactants, and miscellaneous substances) to urine samples positive for amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), tetrahydrocannabinol, heroin, cocaine, or benzodiazepines (diazepam or alprazolam) and tested them with one-component immunochromatographic UDST strips. The UDST for cocaine resisted adulteration the most, while the cannabis test produced the most false negative results. The most potent adulterant that barely changed the physiological properties of urine specimens and therefore escaped adulteration detection was vinegar. Besides lemon juice, it produced the most false negative test results. In conclusion, some urine adulterants, such as vinegar, could pass urine specimen validity test and remain undetected by laboratory testing. Our findings raise concern about this issue of preventing urine tampering and call for better control at sampling, privacy concerns notwithstanding, and better sample validity tests., Preliminarna analiza prisutnosti psihoaktivnih tvari u mokraći pomoću imunokromatografskih testnih traka (UDST) našla je primjenu u mnogim područjima. Iako vrlo prikladne u kontroli zloporabe droga, testne su trake iznimno osjetljive na sredstva za patvorenje (adulterante) kao što su kućne kemikalije, što može značajno promijeniti rezultate testa. Cilj ovoga istraživanja bio je ispitati potencijal uobičajeno korištenih adulteranata kada je riječ o utjecaju na rezultate probira na prisutnost psihoaktivnih tvari u mokraći uporabom UDST-a. Ispitivane kemikalije (kiseline, lužine, oksidirajuća sredstva, površinski aktivne tvari i druge) dodane su uzorcima urina u kojima je, tekućinskom kromatografijom – masenom spektrometrijom (LC-MS) prethodno potvrđena prisutnost amfetamina, 3,4-metilendioksimetamfetaina (MDMA), tetrahidrokanabinola, heroina i kokaina benzodiazepina (diazepam ili alprazolam). U ispitivanju su korištene jednokomponentne imunokromatografske testne trake. Manipulacija uzorcima urina provjeravala se pomoću pH traka, kao i biokemijskih testnih traka za semikvantitativno određivanje koncentracija endogenih tvari i specifične težine uzoraka urina pomoću testnih traka URIT 11G. Rezultati ovoga ispitivanja pokazali su da je test za detekciju kokaina u urinu najmanje osjetljiv na utjecaj ispitivanih adulteranata, a test za detekciju kanabinoida najosjetljiviji, posebice u pogledu lažno negativnih rezultata. Najsnažniji adulterant koji je utjecao na rezultate testa a nije promijenio fiziološke parametre urina je alkoholni ocat. Osim soka od limuna, alkoholni ocat dodan u urin proizveo je najveći broj negativnih ishoda testiranja. Može se zaključiti da značajan broj adulteranata utječe na rezultate testa i da je moguće da neki od njih, poput alkoholnoga octa, mogu proći neopaženo pri kontroli valjanosti uzorka. Ovi nalazi upozoravaju na važnost strogo kontroliranog okruženja za uzorkovanje urina kako bi se spriječile manipulacije.

Published
2020

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