OKay I needed a catchy title... let me be more specific now, my argument is two-fold as spelled out below. I appreciate respectful feedback on these thoughts. I don't really want to fight!
#1 Professional nursing care is the professional assessment and management of a patient's (or community's) health conditions/status/indicators. This may or may not include providing medical diagnoses and making medical/surgical treatment decisions.
#2 "Nursing diagnoses" is a confusing misnomer. "Professional nursing assessments" might better reflect the function of these labels.
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With a license, the nurse has the right to make "professional nursing assessments". Thinking of nursing this way, nursing diagnoses actually make sense (except for calling them 'diagnoses'). It's not that only someone with a nursing license can recognize and identify "diarrhea" or "insomnia", it's that only someone with a nursing license is allowed to apply those labels in professional documentation and communication.
A lay person can often correctly conclude if someone has impaired mobility or confusion or the like. A nursing assistant can - and should - recognize many conditions that professional nursing assessment addresses such as confusion and risk for falls. What the lay person and assistant *can't* do is offer "professional nursing assessment" of the condition. In the same way, nurses can - and should - recognize and identify medical conditions even though they may not be qualified to give professional medical diagnoses.
In fact, lay people often assess and manage their own nursing and medical needs. Many lay people diagnose their own medical conditions and implement treatment plans, but if they want a professional opinion, they go to a doctor/NP/PA. Similary, lay people often assess and manage their own nursing needs, but if they want professional assessment and management, then they need a professional nurse!
(I was inspired to elaborate on this after reading NANDA's FAQs about nursing diagnoses.
NANDA International Nursing Diagnosis Frequently Asked Questions
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