This is an excellent product, have used it in the past. I have read on some of the breeder forums that this product never has a false positive and is above 90% accurate.

Witness Relaxin Pregnancy Test Kit 5ctThis is a fabulous kit that does require a BLOOD sample. You can draw it yourself or have it drawn at your Vet, SPIN IT DOWN to get the plasma (the clear liquid at the top) and the two drops that the Relaxin kit requires. It is simple and easy to use if you have the ability to draw your own blood and a centrifuge at home (get one on Ebay cheap!). Your Vet should draw and spin down the blood for you for very little money. The kit has FIVE tests included, and the price is about the same as ONE test at the Vet. Be sure the blood is put in an EDTA or heparnized tube, then separated if your Vet does it for you. He will just put the plasma in a new tube and for $10.00 for the blood draw, you can do the rest of the test yourself.

when i decided to get it, it was written : use 2 blood drops !
i thought its that easy !
when i got it and after i read the info i got a bad surprise!
do not use hall blood use only plasma !
i don't have a lab in my house!!
also i bought it while these tests are available in my veterinary but i wanted to save money!
to remove plasma from blood U need to fill about two blood test glass and to put in a device for few minutes and of course pay money! :(
it wasn't easy to take the simple, after we toke it the test was negative

it works nice and good
but not for home users!
if i knew am going to the veterinary any way it won't buy it

the thing that make me really unhappy was that the expiring date after one year while it contain 5 teat and i haven't see yes a bitch got pregnant 5 times in 1 year ! This from the seller

am not very happy withe this experience

but the good thing that the test is very fast and gives a current indications