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Identification methods

Any drugs and their metabolites are excreted in urine. Testing for addictive substances is based on the analysis of a urine specimen for their presence. We offer immunological identification methods. False-positive and false-negative results occur in rare cases. As a result, these identification methods can not be considered conclusive. For this purpose, a urine specimen needs to be analysed using a chromatographic method. Testing for addictive substances does not detect opiates, while heroine, morphine and codeine are recorded without a difference.

Duration of the possible identification of various substance groups in urine

The detectability of drugs in urine depends on the consumed quantity of the substance as well as the quantity of fluids the person drank. In addition, the excretion of the substances varies greatly among individuals. The dilation of the urine as a result of the addition of water or because of the consumption of large quantities of fluids is determined based on the Creatinine levels.

Substance group	Duration of the identification in urine	Remarks
Alcohol (ethyl glucuronide)	1.5 to 3 days	One-time alcohol consumption with a blood alcohol content of 0.02 to 0.2 percent

Additional information:

Control of abstinence: ethyl glucuronide is closing the diagnostic gap

Ethyl glucuronide testing (EtG) represents an innovative specific marker. It is a phase II metabolite of alcohol (ethanol), formed by hepatic glucuronidisation and eliminated via the kidneys. Consequently, EtG can be used for the direct identification of prior alcohol consumption. Because the substance is a very stable metabolic product, ethyl glucuronide has not only been identified in urine and serum, but also in hair and post mortem. In contrast to blood alcohol, ethyl glucuronide in the body is decomposed slower and excreted in urine with a delay. Because the half-life of ethyl glucuronide is longer (t½ = 2 – 3 h) compared to alcohol (25 minutes), it is possible to determine an accumulation of the substance in the body in patients with regular alcohol consumption.

In patients with a blood alcohol content of 0.02 – 0.2 percent, ethyl glucuronide in urine can be identified for at least 1 1/2 days (39 hours) up to 3 days, even with a mere one-time consumption of alcohol.

Therefore, the identification of ethyl glucuronide is closing the diagnostic gap between alcohol identification (usually on site) and the currently used long-term markers CDT (approximately 3 weeks), gamma glutamyl transferase (GGT, 1 month) and mean corpuscular volume (MCV). With respect to alcohol abuse, the latter are only indirectly sensitive (with the exception of CDT), while EtG is a direct metabolic product of alcohol.

In the practice, EtG can be identified as early as after the consumption of 10 grams of pure alcohol (corresponding to approximately half a bottle of beer). After the consumption of alcohol, the maximum EtG concentrations are only reached with a delay of approximately 2 to 3.5 hours with respect to the blood alcohol content. The alcohol levels in blood drop below the identification level of common tests after 5 – 7 hours, while the EtG concentration in serum reaches its maximum significantly later.
After excessive alcohol consumption, EtG can be identified in urine for up to 80 hours. A study was conducted with relatively small quantities of alcohol as they are common in alcoholics during withdrawal therapy. It was shown that ethyl glucuronide can still be identified in urine 19 to 27 hours after a one-time consumption of only 9 grams of alcohol. The maximum concentration was reached after 3 to 10 hours.
For the standardised evaluation of determined ethyl glucuronide concentrations, the standardisation of ethyl glucuronide values for creatinine content determined in urine is meaningful, because there is no evidence of a BMI (body mass index) or gender-specific correlation.

Moreover, the determination of ethyl glucuronide also allows a review of the alcohol abstinence of the previous day, if there is no evidence of alcohol in both the blood and urine.
A conclusion with respect to the consumed alcohol quantity is only possible if the ethyl glucuronide levels in the serum exceed 1.5 mg / L. In this case, the measured blood alcohol content would have been at least 0.16 percent. A retrospective extrapolation to the exact blood alcohol content via ethyl glucuronide identification is not possible. Ethyl glucuronide was exclusively detected in the hair shaft of persons with regular alcohol consumption. Therefore, it is not suitable as a screening method for recent alcohol consumption.
Due to the prolonged elimination time of EtG, spontaneous urine represents the specimen material of choice. At room temperature, the EtG concentration in urine is stable for 140 hours. Consequently, the specimen of spontaneous urine can be mailed to us without cooling.
In addition to the determination of EtG, the measurements based on established methods to detect chronic alcohol abuse (CDT, hepatic enzymes, MCV) will continue to be part of the diagnostic procedures.

Required materials: at least 2 mL of spontaneous urine. It can be transported at room temperature.

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