When they tested me, albeit some years ago and for slightly different reasons, the specimen had to be at the path lab within 30 minutes of leaving me.
We lived 45 mins away by car and they rejected the first try as "Too old to be of any use" so it was try again only this time we parked up at the back of the 9th at the local golf club and got the specimen to the hospital in 5 minutes.

Thank the Lord it was pissing down and nobody was out looking for lost balls or they would have found more than they expected.