Final answer:
For a blood alcohol test, a phlebotomist should use 70% isopropyl alcohol as an antiseptic to avoid interference with the test results, as alternatives like Betadine could be falsely detected as alcohol in the sample.
Step-by-step explanation:
A phlebotomist is performing a blood alcohol test. The antiseptic they should use for this procedure is 70% isopropyl alcohol rather than an iodine-based solution like Betadine.
The reason for this selection is to avoid interference with the alcohol test results, as the iodine can be falsely detected as alcohol in some testing protocols. The use of 70% isopropyl alcohol is effective for sanitizing the site of the blood draw while preventing any contamination of the blood sample that could affect the outcome of the test.