Blood-alcohol tests can be inaccurate if the needle is sterilized with ethanol, a research group said Friday.

The group, headed by Yoshinao Katsumata, a professor at Nagoya University, said that in its experiments, ethanol was found mixed in with the blood samples, producing readings that said the sober subjects were slightly drunk to heavily drunk.

According to the study, there was little ethanol in the samples if the needle was used after the ethanol evaporated.