SOLVED. nowing your own scope of practice and the limitations and abilities of each level of nursing certification is essential to competent practice and to avoid being sued for practicing outside of your scope. In the U.S., there exist three levels of nursing certification, each with ascending educational requirements and scope of practice: LPNs, RNs, and APRNs. LPNs require the least formal education and can assist RNs with assessments, reinforce teaching, and be trained to perform most nursing tasks (Ernstmeyer