Thank you. This test was given to me by my vet a few months ago, I'm only trying it now. Since I don't want to go back there, I can't ask her. This test sounds convenient, but not so in reality. I used a non-clumping litter, but the few flakes that were in contact with urine were buried under the litter. To break a clump would be kind of "yuk"...Anyway, someone just told me that this product is now discontinued, for valid reasons I suppose.