- Testing should be performed a minimum of 6 hours after loss of last brain stem function
- Longer period should be given in atypical presentations:
- A minimum of 24 hours should be given if primary aetiology hypoxic brain injury
- Prolonged observation may be required in cases of unclear aetiology
- No statutory interval must elapse between the tests, but this should be sufficient to reassure all those involved
- Legal time of death is retrospectively noted as the time the first set of tests confirms brainstem death, though death is not declared until after the 2nd test