Final answer:
Isopropyl alcohol is the antiseptic that should be used when performing a blood alcohol test. It acts by denaturing proteins and disrupting membranes, making it effective in killing microbes.
Step-by-step explanation:
The antiseptic that should be used when performing a blood alcohol test is Isopropyl alcohol. Isopropyl alcohol, also known as rubbing alcohol, is a commonly used antiseptic that acts by denaturing proteins and disrupting membranes. It is effective in killing microbes, including bacteria and viruses.