what is the latest in gestation that any of you have experienced a false negative using the relaxin test?

false negative can happen if you do the test earlier than day 30 or if the bitch is only carrying one pup. there might not be enough relaxin hormone to trigger the test. day 35 - 38 should be sufficient.

from what starting point are you calculating the day to do the test? LH surge? Progesterone 5 ng? day of breeding? day of first breeding? day of last breeding?

I don't do relaxin. It is cheaper for my vet to do a quick sonogram. No head count, just to confirm pregnancy.

relaxin test are cheaper than sono grams for me. The only time I do them is if planning events requires me to know.

I do them 32 days after ovulation, have always been correct.

I don't do sonograms anymore. I have had them show 6+ puppies, you get all excited, hopes up then they reabsorb after the sonogram :o(

Relaxin test is never 100% reliable

it is always reliable as long as you understand how it works.

Dont test so darn early, wait till at least day 35 post ovulation. It wont be wrong.

False negatives are from early testing or single pup and still to early testing.

no such thing as a false positive, if you get a positive your dog is or was pregnant at the time of testing.

I tested my girl at day 28 post ovulation, which the insert says is 100% reliable. She was negative. Now I am trying to decide what to do.

I don't think so. A friend of mine owns 2 Springers, a male and a female. He had plans to breed them one day, provided they both passed their health clearances. The female had her first heat cycle before she turned a year old. I took her during her heat so that he wouldn't have to worry about them breeding. I have no intact boys. Approximately 7-8 weeks later, he went on vacation and I watched both dogs again. I noticed his female appeared to have some mammary development and looked a little fat. I was freaked out because she was still just a puppy. I took her to the vet for a relaxin test and it came up positive. When he came home a week later, I told him and he took her to the vet for an x-ray. No puppies. The vet couldn't tell me why her relaxin test popped positive, but it did. No way she reabsorbed puppies that far along in one week.

the only way you can get a positive reading is by the test confirming that there is relaxin in the blood stream....the only way relaxin can be in the blood stream is if the dog has a growing placenta in the uterus that is producing the relaxin..... AT ONE TIME....which would probably mean your friends dog was pregnant and had already started to absorb the litter before she came to your house.

In fact, there is another way that you could get a positive without being pregnant--false positive. All tests have error. The question is how much error and when and what kind of error.