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barbiturate in urine

Indications: - drug abuse: barbiturates Reference values: - Not applicable Clinical significance: The urine barbiturate assay is used to qualitatively screen barbiturates 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. Principle: The Urine Barbiturate pack is used in the DuPont ACA discrete clinical analyzer to qualitatively detect barbiturates 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 barbiturates antibody & the barbiturate-glucose-6-phosphate dehydrogenase conjugate. The concentration of barbiturates in the sample determines the amount of barbiturates - glucose-6-phosphate dehydrogenase (BARB-G6PD) conjugate that is bound to the barbiturates 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 barbiturates in the sample by means of a calibration curve or a mathematical function. 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.

Specific

barbiturate qualitative in urine barbiturate quantitative in urine

General

drug of abuse test barbiturate in body fluid urine toxicology

References

  1. ACA IV Discrete Clinical Analyzer Instrument Manual, Volume 1: Operation, DuPont Company, Wilmington, Delaware, 1984.
  2. ACA IV Discrete Clinical Analyzer Instrument Manual, Volume 3B: Chemistry, DuPont Company, Wilmington, Delaware, 1984.
  3. Drug Confirmation, Barbiturates, Urine Laboratory Test Directory ARUP: 90357
  4. Panel of 10 tests Laboratory Test Directory ARUP: 90448
  5. Panel of 11 tests Laboratory Test Directory ARUP: 90449
  6. Panel of 35 tests Laboratory Test Directory ARUP: 90453
  7. Panel of 13 tests Laboratory Test Directory ARUP: 90454
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