It is now universal policy in the UK, Europe, US and in many other countries to dispose used needles WITHOUT removing the sheath, or if the needle is already exposed, WITHOUT re-sheathing. It’s a simple policy – don’t consider any additional manoeuvre since this could increase the possibility for accidental sharps injury.
But removing a needle sheath is of course essential before use, and in circumstances where needle change is required after drawing up a drug from a vial before changing to a fresh needle to inject a patient. These can be three-handed manoeuvres and when help is not available all sorts of inappropriate things can be seen – chasing the sheath across a table top in the hope of scooping it up with the needle tip, even holding the sheath between teeth!
So the FDA approved Ingenious Technologies Corp Needlesafe II seems to have a place, at least in selected circumstances.
The Ingenious webpages (http://www.ingenious.com/NS/ns.htm) give plenty of helpful information but make no reference to the widely accepted principle of disposal without recapping. Moreover, and perhaps more significantly for a device that is intended to be fixed into position with adhesive and thus not easily removed, there is no mention of hygiene, to ensure that the Needlesafe II and its surroundings are not splattered with blood or drug substance.