[The reliability of instruments for measuring breath alcohol]

To describe the reliability of breath-alcohol testers, values are measured which characterize precision, accuracy, analytical sensitivity, drift, and hysteresis. The instruments tested were two infrared devices (Alcomat, Alcotest 7110) and one device equipped with a fuel cell (Alcolmeter EBA). Criteria of acceptability are the limits from the first preliminary draft of recommendations by the Organisation Internationale de Métrologie Légale (OIML). The results of measurements clearly show the level of reliability of modern instruments which largely attain the OIML requirements. All measurements were performed with a simulator at 34 degrees C. Therefore the definite influence of breath temperature on the alcohol concentration could be neglected.