U.S. flag

An official website of the United States government, Department of Justice.

NCJRS Virtual Library

The Virtual Library houses over 235,000 criminal justice resources, including all known OJP works.
Click here to search the NCJRS Virtual Library

Ability of Subjects With Impaired Respiratory Function to Provide a Satisfactory Breath Sample for the Alcotest 7410 Breath Alcohol Device

NCJ Number
Canadian Society of Forensic Science Volume: 31 Issue: 4 Dated: December 1998 Pages: 269-274
T S Hurst
Date Published
6 pages
This study tested the ability of persons with impaired lung function to provide a breath sample using a device that is currently approved and widely used: Alcotest 7410 GLC.
The device was initially bench tested in the research laboratory. Using a calibrated pressure transducer and flow meter, a series of tests was performed to ascertain the inlet pressure required to produce various airflow rates while the instrument was operating. These tests were performed with a mouthpiece attached. The tests also determined the time required for the device to cycle at the various flow rates, thus measuring the total volume of gas required to operate the device with various gas flows. This test series also determined the minimum inlet pressure and flow required to operate the device. After bench testing was completed, the device was transferred to the Pulmonary Function Laboratory. After patients had completed their diagnostic tests, they were asked if they would attempt to provide a suitable sample into the Alcotest. The respiratory ailments of the patients varied from a mild cough to serious impairment. The ability of these patients to provide an acceptable sample was correlated with their pulmonary test results. Results show that subjects with a forced vital capacity of less than 1.25 liters failed to provide an acceptable sample; one-third of those with a vital capacity between 1.25 and 1.75 liters also failed; only a small number (3 of 80) of those with a vital capacity greater than 1.75 liters failed. The limiting factor in the ability to provide a satisfactory sample for the Alcotest 7410 was the patient's vital capacity, rather than his/her ability to produce high respiratory pressures or flows. 4 figures and 9 references