I’ve never been told to use a wipe prior to finger sticking, and I’ve heard of people injecting through clothing at times. How necessary is it to use an alcohol wipe prior to injection?

Alcohol is important in order to avoid infection at the site of the injection. You are theoretically removing bacteria that might otherwise move through the break in the skin and cause an infection. You could use soap and water which does almost the same thing for both your fingers and injection sites.

JTL
Additional comments from Barb Schreiner, diabetes nurse specialist:

Investigators at Wayne State University asked that very question about injecting insulin through clothing. They studied 50 people for 20 weeks and concluded that injecting through clothing is safe and convenient. They reported their results in 1997 in Diabetes Care. See The safety of injecting insulin through clothing (Diabetes Care, 1997. 20(3):244-7).

BS
Additional comments from Jane Seley, diabetes nurse specialist:
In my many years of experience taking care of people with diabetes, I have met many many people that inject insulin without using alcohol through panty hose, jeans, etc. At the same time, I can count on one hand how many infections I have seen from doing this. The only exception to this is insulin pump patients who leave the “set” in for many days beyond what is recommended. That is different than injecting and removing a needle immediately after.

JS