From the Guidelines
Alcohol is unlikely to be detected in a urine drug screen the morning after consuming three drinks between 5-9 PM. The body metabolizes alcohol at a rate of approximately one standard drink per hour, so three drinks would typically be eliminated from the system within 3-5 hours after the last drink. By the next morning, which would be at least 8-12 hours after the last drink at 9 PM, the alcohol would have been fully metabolized by the liver.
Detection Window
Urine alcohol tests detect ethanol and its metabolites, primarily ethyl glucuronide (EtG), but standard urine drug screens typically only detect alcohol for up to 12-24 hours after consumption for moderate drinking 1. The detection window depends on several factors including the individual's metabolism, body weight, food consumption, and liver function.
Factors Influencing Detection
If someone is concerned about alcohol detection, staying hydrated and allowing sufficient time between drinking and testing will increase the likelihood of a negative result. However, it's essential to note that certain tests, such as those detecting EtG, can remain positive for up to 80 hours depending on the level of alcohol intake 1.
Test Sensitivity and Specificity
The sensitivity and specificity of urinary EtG for detection of alcohol use were 89% and 99%, respectively, among patients with ALD before and after LT 1. Phosphatidylethanol (PEth) is another marker with a high sensitivity and specificity for detecting alcohol consumption, especially in patients with chronic liver disease 1.
Real-World Application
In real-life clinical practice, the likelihood of detecting alcohol in a urine drug screen the morning after moderate drinking is low, but it's crucial to consider individual factors and the type of test used. The most recent and highest quality study suggests that alcohol is unlikely to be detected in a urine drug screen the morning after consuming three drinks between 5-9 PM 1.
From the Research
Alcohol Detection in Urine
- The detection of alcohol in urine is typically done through the measurement of ethyl glucuronide (EtG) and ethyl sulfate (EtS) levels 2, 3, 4, 5.
- EtG and EtS are conjugated ethanol metabolites that are formed in low amounts after alcohol consumption and are excreted in urine for a prolonged time, making them useful as sensitive alcohol biomarkers 4.
- The detection time for urinary EtG and EtS can vary depending on several factors, including the amount of alcohol consumed, the frequency of consumption, and individual differences in metabolism 4, 6.
Detection Times for EtG and EtS
- Studies have shown that EtG can be detected in urine for approximately 40-130 hours (median 78 hours) after alcohol consumption, with a similar time course observed for EtS 4.
- After correction for urine dilution, the time until an EtG/creatinine ratio <0.5 mg/g was approximately 40-90 hours (median 65 hours) 4.
- The detection times for EtG and EtS can show wide inter-individual variations, even after adjusting for urine dilution and estimated times for completed ethanol elimination 4.
Implications for Urine Drug Screening
- Given the detection times for EtG and EtS, it is possible that alcohol may still be detectable in urine the morning after consumption, even if the individual has not consumed alcohol for several hours 4, 5.
- However, the exact detection time will depend on various factors, including the amount of alcohol consumed and individual differences in metabolism 4, 6.
- Urinary EtG and EtS testing can be a useful tool for objective identification of recent drinking in individuals undergoing treatment for alcohol dependence 3, 5.