Alcohol itself is usually measurable in blood for a few hours up to about a day, and in urine for about one to three days. Markers of a use pattern look back further: CDT in blood about two to three weeks, EtG in hair up to around three months. The window therefore depends heavily on the matrix.
Below you will find what is realistic per matrix, so you can choose the test that fits your question.
How long does alcohol stay detectable per matrix?
The detection window differs greatly between blood, urine and hair. Blood shows very recent use, urine a little longer, and hair captures a pattern over months.
| Matrix | What it measures | Approximate window |
|---|---|---|
| Blood (alcohol) | Recent use | Hours to ± 1 day |
| Urine (EtG) | Recent use | ± 1 to 3 days |
| Blood (CDT) | Pattern, chronic use | ± 2 to 3 weeks |
| Hair (EtG) | Pattern over a longer time | ± 1 month per cm, up to ± 3 months |
Which marker is useful depends on the time window. For a pattern over recent weeks, CDT is often used. For the markers the CBR includes, read CDT value and your driving licence.
Why a lab instead of a home test?
A home test gives a yes/no signal with a wide margin of error. A lab quantifies a value per marker with a reference range. In a borderline case, that can make the difference between doubt and a result you can support. More context is in the overview of proving alcohol use.
Every blood test result at Zuivertest includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
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