Have you ever tried to get pee from cats? No? Then let me school you.
First you empty out their litter boxes and separate the cats. Hours later, you realize that these cats are no suckers and will not use an empty litter box. They need something to dig in, dammit!
Next you shred some glossy newspaper inserts and put the festive confetti in the litter boxes. It looks pretty. And it works the first time around. Success!
The next time you need a sample you try the same shredded paper trick. Hours later you realize that the cats subscribe to the worldview of: "Fool me once, shame on you; fool me twice, shame on me." They will not pee on shredded paper. They will, however, nestle down into the litter box, get all com-fer-tuh-buhls and look at you smugly, as if to say: "Ah, this is a nice new place to nap. Look at me. I'm lying down, not peeing."
You also begin to marvel at their ability to hold out for over 12 hours. This is determination, people.
So you decide to try a new vet-approved option: Lentils. Theses little legumes mimic the look and texture of kitty litter but won't absorb the sample. (If you get there in time, that is.)
You put 16 ounces of lentils in the litter box. Your 15-pound cat scoffs at this attempt to fool him. Eventually you add another 64 ounces of lentils to the box and he succumbs to the illusion.
The next time you need a sample, you think, "Hey, no problem. I'm a cat-urine-collecting-pro! All I need are five bags of lentils per cat." So you send your husband to the store to buy 10 bags of lentils.
At the checkout counter the clerk says, "Looks like somebody is making soup!"
Sort of. Lentil and pee soup! Hahahah! (how could I resist?)
You follow protocol: Separate cats; empty litter boxes; fill boxes with lentils. The next morning, Gatwick the Catwick decides that he's really had enough of this and pees in his bed. The boy has never peed anywhere before but in the litter box. But today he decides that he'd rather pee in a cardboard box with a blanket than set foot on your stupid lentils! This act of defiance leaves you both angry. You pick him up to show him the litter box and he scratches your arm tyring to get away from the offending lentils!
Finally, as an act of contrition and in an attempt to make up with his frustrated and exhausted owner, the cat pees in the damn lentils. You use a plastic syringe or eyedropper to collect the sample.
Of course, two cats won't pee at the same time. And samples need to be less than eight hours old. So sometimes you make the 50-minute round trip to the vet's office twice per round of samples.
And you can't bring yourself to make lentil soup for at least a month.