EVALUATING THE VARIABILITY OF DUPLICATE BREATH ALCOHOL ANALYSES AS A FUNCTION OF SUBJECT AGE

The influence of the person's age upon reproducibility in duplicate br eath alcohol analyses is investigated. A total of n = 30,324 duplicate results (with both greater-than-or-equal-to 0.01 g/210L) were selecte d and divided into eight age groups from 10-19, 20-29, and up through 80+. Two duplicate agreement criteria, +/- 10% of the mean and +/- 0.0 2 g/210L, were evaluated according to age. A X(trend)2 analysis was em ployed and resulted in: +/- 10% of mean criteria, P < 0.001 and +/- 0. 02 g/210L criteria, P > 0.05. The proportions of duplicates not confor ming to the two agreement standards along with 95% confidence interval s were: +/- 10% of mean, 0.026 (0.024 to 0.028) and +/- 0.02 g/210 L, 0.052 (0.050 to 0.054). Depending on the agreement criteria selected t here will be proportional differences, but neither appears to be impor tantly influenced by the subject's age. The breath sampling criteria e mployed in the instrument studied does not appear to inhibit acceptabl e agreement, even in elderly subjects where the risk of respiratory di sfunction increases.