semen sample - how long does it last?

[wheatbeer]

I want to remain incognito for this.
Could anyone tell me how long a semen sample remains viable? We are having fertility tests done, and DH has to give a semen sample. The only problem is it is half an hour drive to the hospital - will he have to - ahem - produce the sample in the hospital toilets, or could he do this in the comfort of home?

ooh i thought it wasn't very long.. maybe half an hour or something
they will probably have a room there for the purpose

Oh dear, I think this could be difficult!