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Barbiturates assay

Product Method Size Catalog Price Quantity
Barbiturates assay Homogeneous Enzyme Immunoassay R1 2 x 16.9ml , R2 2 x 8ml DA4008 $647.20
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  • Format
    Liquid ready-to-use
  • Assay Range
  • Working Stability 2-8 °C
    Stable to expiry
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Intended Use

The Barbiturates assay is an in vitro diagnostic test for the qualitative and semi-quantitative detection of Barbiturates in human urine on the RX imola and RX daytona. The cut-off for secobarbital is 200 ng/ml; see cross reactivity section for information on cross-reactivity with other barbiturates.

This assay provides only a preliminary analytical result. A more specific alternative chemical must be used in order to obtain a confirmed analytical result. Gas Chromatography/ Mass Spectrometry (GC/MS) is the preferred confirmatory method. Clinical consideration and professional judgement should be exercised with any drug of abuse test result, particularly when the preliminary result is positive.

Clinical Significance

Barbiturates are central nervous system depressants. They are used therapeutically as sedatives, hypnotics, and anticonvulsants. Barbiturates are almost always taken orally as capsules or tablets. The effects resemble those of intoxication with alcohol. Chronic use of Barbiturates leads to tolerance and physical dependence. Short acting Barbiturates taken at 400 mg/day for 2 to 3 months produces a clinically significant degree of physical dependence.

Withdrawal symptoms experienced during periods of drug abstinence can be severe enough to cause death. Only a small amount (less than 5%) of most Barbiturates are excreted unaltered in the urine. The detection period for the Barbiturates in the urine is 4 to 7 days.


The assay is based on competition between drug in the sample and drug labelled with the enzyme glucose-6-phosphate dehydrogenase (G6PDH) for a fixed amount of antibody in the reagent. Enzyme activity decreases upon binding to the antibody, and the drug concentration in the sample is measured in terms of enzyme activity.

In the absence of drug in the sample, barbiturates-labelled G6PDH conjugate is bound to antibody, and the enzyme activity is inhibited. However, when free drug is present in the sample, antibody would bind to free drug; the unbound barbiturates-labelled G6PDH then exhibits its maximal enzyme activity. Active enzyme converts nicotinamide adenine dinucleotide (NAD) to NADH, resulting in an absorbance change that can be measured spectrophotometrically at 340 nm.

Available Applications

RX series instruments, including:

RX daytona

RX imola