amphetamines in urine
Indications
- assessment of drug abuse, amphetamines
Reference interval
- negative
Principle
The Urine Amphetamine pack is used in the DuPont ACA discrete clinical analyzer to qualitatively screen amphetamines in human urine. It is an adaptation of Syva's homogeneous enzyme immunoassay technique, EMIT. The reagents used in this methodology are matched lots of amphetamine antibody & the amphetamine derivative - glucose-6-phosphate dehydrogenase conjugate. The concentration of amphetamines in the sample determines the amount of amphetamine derivative - glucose-6- phosphate dehydrogenase (AMP-G6PD) conjugate that is bound to the amphetamine antibody. The unbound conjugate catalyzes the oxidation of glucose-6-phosphate, with the simultaneous reduction of NAD to NADH, more rapidly than does the bound conjugate. The rate of increasing absorbance at 340 nm due to the increase in NADH is related to the concentration of amphetamines in the sample by means of a calibration curve or a mathematical function.
Clinical significance
The urine amphetamine assay is used to qualitatively screen amphetamines in human urine. This test provides only a preliminary analytical test result. A more specific alternate chemical method must be used in order to obtain a confirmed analytical result. Gas Chromatography/Mass Spectrometry (GC/MS) is the preferred confirmatory method. Clinical consideration & professional judgement should be applied to any drug of abuse test result, particularly when preliminary positive results are used.
Methods
Specimen
Patient preparation: No special patient preparation is required.
Urine samples should be collected in clean, unbreakable, & leak proof containers. Freshly voided urine specimens should be used. If not analyzed immediately, samples should be stored refrigerated. Refrigerated storage exceeding 3 days, however, may result in positive samples with drug concentrations around 0.30 ug/mL assaying as falsely negative. Drug-free samples have not been observed to produce positive results following storage.
Samples should be within the pH range of 5-8. Samples with pH outside this range should be adjusted to this range by the addition of 1 N HCl or 1N NaOH before assaying. Specimens may be encountered that display high turbidity. It is recommended that these be centrifuged before analysis.
Interferences
- NaCl causes false negative results
- EIA: labetolol, ranitidine & certain phenothiazines may cause false positive results
- aripiprazole may cause cause falsepositive results
More general terms
Additional terms
References
- ↑ ACA IV Discrete Clinical Analyzer Instrument Manual, Volume 1: Operation, DuPont Company, Wilmington, Delaware, 1984.
- ↑ ACA IV Discrete Clinical Analyzer Instrument Manual, Volume B: Chemistry, DuPont Company, Wilmington, Delaware, 1984.
- ↑ Stimulant Amines Detection Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0090302.jsp
Drug Confirmation, Amphetamines, Urine Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0090439.jsp
Panel of 10 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0090448.jsp
6) Panel of 11 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0090449.jsp
7) Panel of 35 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0090453.jsp
Panel of 13 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0090454.jsp
Panel of 8 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0090491.jsp
Panel of 9 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0090492.jsp - ↑ Kaplan J, Shah P, Faley B, Siegel ME Case Reports of Aripiprazole Causing False-Positive Urine Amphetamine Drug Screens in Children. Pediatrics. October 2015 <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/26527556 <Internet> http://pediatrics.aappublications.org/content/early/2015/10/28/peds.2014-3333