What Can an RN Do That an LPN Cannot?
The short answer: the RN license authorizes independent nursing assessment, care planning, and supervision — the "thinking and directing" layer of nursing — while the LPN license authorizes hands-on care delivered under direction. The exact boundary is drawn by each state's nurse practice act, so the honest answer to "what exactly can't an LPN do?" always ends with "check your state."
The general pattern
Across states, the same broad division shows up again and again. RNs typically can, and LPNs typically cannot:
- Perform the initial, comprehensive patient assessment. LPNs collect data — vital signs, observations, changes in condition — but the formal assessment that anchors a patient's care is generally RN work.
- Create and modify the nursing care plan. LPNs carry out and contribute to the plan; building and changing it is generally reserved to the RN.
- Administer the full range of medications and therapies. Many states restrict LPNs from certain higher-risk routes and treatments, particularly some IV medications, or require extra certification for them.
- Supervise other nursing staff. RNs direct LPNs and nursing assistants; the reverse doesn't happen.
- Handle the most complex and unstable patients. As acuity rises, so does the requirement for RN-level judgment.
The American Nurses Association's scope-of-practice materials are the professional reference for how these layers of nursing practice are defined, and they're clear that scope is a function of education, licensure, and state law together — not job title alone.
Why the line moves from state to state
Nursing is regulated state by state. One state may permit LPNs to start IVs with a certification; a neighboring state may not. One state may allow LPNs broader medication authority in long-term care than in hospitals. This isn't sloppiness — it's fifty-plus separate nurse practice acts, each written by its own legislature and interpreted by its own board. The NCSBN directory of state boards links every board; if a specific task matters to your decision, the board's published rules are the only answer that counts.
Where the difference comes from
The scopes differ because the preparation differs. RN programs — the two-year ADN or four-year BSN described in the AACN's fact sheets — spend far more time on pathophysiology, pharmacology, and clinical judgment than a one-year practical nursing program can. The licensure exams mirror this: the NCLEX-RN tests a broader and deeper range of clinical decision-making than the NCLEX-PN, as the NCSBN's exam materials lay out. The license line follows the education line.
What this doesn't mean
It doesn't mean LPNs are "less than." In long-term care especially, experienced LPNs are often the professionals who know residents best and notice changes first. The scope difference is about legal authority and accountability, not about who works harder or matters more.
It also doesn't mean the line is permanent for you personally. LPN-to-RN bridge programs exist precisely to carry practical nurses across it, often with credit for what they already know. If that's the route you're weighing, start with our LPN vs RN overview and the LPN-to-nurse-practitioner page, which maps the longer ladder.