I asked this same question awhile back, because Winston will only pee in the grass...I swear he'd explode before he would pee in the house...But someone suggested a dipper or ladle...just follow them around outside and catch it...don't see how this would work, but some one said it does. Lucky for me I've never had to do it. The vet should have gotten the sample...
__________________ As Ever, Kathy 
Intruducing Bentley  Winston and Spencer: RIP My Sweet Angels |