actually it's called an NCV (nerve conductance velocity).....although an EMG may be a good place to start as they are generally cheaper.
also, you didnt elaborate...is it your whole hand....if it is then it is less likely an entrapment as they generally follow dermatomal distribution.
Also check what is called "capillary refill" to see if it is a vascular problem.....basically just squeeze your fingernail for a sec till it turns white then let go....it should get pink/red again very quickly...compare it to your good hand...they should be equal...if not...maybe look into seeing a vascular specialist.
but do describe your symptoms in more detail.