I've not heard of a CNS. I'm also not a nurse, but mrsskoorb has talked about them, so I can divulge a little. LPNs are not as "high up" as a registered nurse. They have less responsibilities and training, and lower-end duties, such as a higher ratio of crap-cleaning up than an RN would. I wonder if your CNS definition = RN? When joe blow on the street thinks of "nurse" they generally think not of an LPN, but of an RN.