You dont have to have any BUT micro, chem, math, anatomy and english classes would be ideal if you need to brush up on those sections...the math is very simple pre-algebra math...make sure you get the ATI TEAS study book. It will help you a lot. Having taken micro right before I took the TEAS helped...it all depends on what your school requires as pre/co reqs too
I am taking a basic A&P class right now, I will be taking an algebra refresher, CHEM 1, intro to healthcare and CPR/First Aid for the medical worker starting in May. I have to take the TEAS V by mid July.
I just did the first 4 practice tests, I had the most trouble with the english & language section and a close second to the science. Lucky for me I have till May to take the TEAS V for the first time and Aug if I need to take it a second time.