Information hub
Clear, evidence-based guides to drug, alcohol and DNA testing across the UK and Ireland. Written by NIVHA, which runs testing programmes across the UK and Ireland, with analysis by ISO 17025 accredited laboratories — how testing works, what results mean, and how to choose the right test for your situation.
This page is a general guide. It is not legal, medical or technical advice. Laws, guidance and laboratory methods change, so check the current requirements for your own case. Last reviewed .
How long do drugs and alcohol stay in your system
Detection windows for urine, oral fluid, hair and nails, with a substance-by-substance guide.
Legal DNA testing for court use in the UK and Ireland
What makes a DNA test suitable for court use, and what solicitors and social workers need to know.
Hair drug and alcohol testing: the complete guide
How hair testing works, segmentation, alcohol markers and the limits of the method.
Drug and alcohol testing in the workplace
An employer’s guide to test types, consent, medical review and defensible policy.
The workplace drug and alcohol policy
Why the policy comes before testing, what a defensible one contains, jurisdiction differences and where templates fall short.
Understanding your test result
What positive and negative mean, cut-off levels, confirmation and medical review.
Hair, nail, blood or urine: choosing the right sample
A decision guide across every sample type, by what the case needs to show.
Chain of custody explained
Why a documented, tamper-evident process matters for court and tribunal work.
DNA relationship testing beyond paternity
Siblingship, grandparent and immigration testing when the alleged father is unavailable.
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