Can I say - “N’est-elle pas?” as a translation for “Isn’t she?”

Hi Neil, 

No, you will not use -

"N'est-elle pas?", on its own, for "Isn't she?"

It will be -

n'est-ce pas?

e.g.

Martine, n'est-elle pas malade? =  Isn't Martine ill? 

But

Martine est malade, n'est-ce pas? = Martine is ill, isn't she?

Hope this helps!