Abstract
Since 1 October 1989, the Netherlands has a legislation concerning driving under the influence of alcohol that has primarily been based on the breath test. The blood or urine tests are only applied in exceptional cases. Nevertheless, about 350 blood or urine samples reach the Forensic Laboratory each month, with the purpose of determining the blood alcohol content. There can be various reasons to carry out a blood test in the place of or besides the breath test. By means of a questionnaire conducted among the suppliers of blood samples, it is tried to get an impression of the reasons playing a role in practice.