Can I ask for a blood or urine test instead of a breath test in Northern Ireland?

The statutory scheme normally uses evidential breath where it can lawfully and reliably be taken. A constable can require blood or urine in defined situations, for example where breath cannot be provided or should not be required for medical reasons, or where the approved breath equipment is unavailable or unreliable.

Older “statutory option” rules have changed over time, so motorists should not rely on old advice suggesting every borderline breath reading lets the driver demand blood or urine. The current legislation and police procedure control which specimen is required.

Failing to provide the specimen lawfully required, without reasonable excuse, can itself result in prosecution.

The NI enforcement process separates screening from evidential proof. A roadside breath test, DrugWipe or impairment check gives police information and may justify arrest or further testing, but the prosecution is built from the statutory evidential procedure, officer observations and any laboratory or approved-device result. That distinction matters when reading reports of someone having “failed a roadside test”. For the driver or keeper, this means not simply because you prefer it. Blood or urine replaces evidential breath only in circumstances allowed by Northern Ireland law; the choice is not generally the driver’s. Where dates, categories or vehicle status matter, keep the original paperwork because those details can change the result.