Large-scale breath-blood comparisons under field conditions : methods, evaluation techniques and results.

This work, part of a long-term study of comparisons of breath (BRAC) and blood alcohol (BAC) under widely varying conditions, has the overall aim of investigating whether blood sampling can be substituted by breath, and comprises the results in the field of breath-blood comparisons on over 1000 drivers suspected of driving under the influence. Results show that reliable automated breath methods with digital printout, consistent performance and a variability between repeated samples under statistical control within fixed limits related to the BRAC level, can be substituted for blood sampling in the overwhelming majority of cases. The measures to be taken in the few cases left are under further investigation.