A study concerning the blood/breath alcohol conversion factor Q: concentration dependency and its applicability in daily routine.

The conversion factor Q, obtained by division of blood alcohol concentration (BAC) by breath alcohol concentration (BrAC) is a widely discussed topic due to its great variance. By Austrian law, regulations frequently require an estimation of a corresponding BAC by a measured BrAC. It is known that Q depends among other things, on the alcohol kinetic state of the person being tested, which mathematically can be transformed to a dependency on the BrAC. Theoretically calculated Q values per BrAC level form a hyperbola shaped curve, thus decreasing with increasing BrAC values. Applying Austrian forensic standards for BAC and BrAC measurements, these calculations were verified in a study under practical conditions with BAC and BrAC data of 390 individuals. Q decreases from 2629 (+/- 455) for BrAC levels < 0.1 mg/l to 2229 (+/- 160) for a BrAC range of 0.4-0.5 mg/l and increases again to 2428 (+/- 124) for BrAC levels > 0.6 mg/l. Since these results were obtained under realistic practical conditions they can be directly applied in routine forensic expert opinion and can eliminate avoidable variances in the calculation of Q.

Cross-reactivity of the CEDIA buprenorphine assay with opiates: an Austrian phenomenon?

When testing the Microgenics CEDIA assay for immunological buprenorphine analysis, cross-reactivity between the buprenorphine reagents and opiates was observed at concentrations higher than 120 mg/l morphine, 320 mg/l methadone, 30 mg/l codeine, 60 mg/l dihydrocodeine and 520 mg/l morphine-3-glucuronide. The cross-reactivity with morphine has the greatest impact on routine screening as opiate maintenance therapy in Austria is also performed with slow-release oral morphine. The use of a second cutoff value of 30 mug/l for urine samples that are (immunologically) positive for opiates is therefore suggested, compared to the cutoff value of 5 microg/l proposed by the manufacturer.