What's the difference between pregnancy tests that check urine and those that test blood? Which one is better?

Blood tests are more accurate for pregnant test, plus you can get that tests earlier then the urine test.

Urine tests are usually the pilimary testing to pregnancy. There is a fail rate, but it's truely VERY small.
If you aren't showing symptoms of a pregnancy but yet you believe you are pregnant and such, doctors will do a blood test which is the end all be all of pregnancy test - like the gold standard.
Usually during your first prenatal exam, they take your blood to still verify. Of all the pregnancy tests I have taken, all of them have been correct. Check out the link supplied below.

both tests trigger a positive reading if there is a certain level of progesterone (a hormone that is produced when you are pregnant) in your body. the problem with urine tests is that they are less effective if you have high levels of certain chemicals in your body, like THC and niacin. blood tests however, are much more accurate, and expensive. most women use urine tests, most of which are 99% or more accurate, to get an idea if they are pregnant, then get a blood test to confirm it. the best way to use a urine test is to use it the first time you pee in the morning because your urine is much more concentrated and carries higher amounts of the progesterone hormone. i hope this was helpful and if you have any other questions, feel free to email me at my email address in my profile. good luck!

The old fashioned urine tests have improved dramatically over the years. The error rate has dropped to almost zero. In times past (and I don't want to date myself) you really couldn't rely solely on the over the counter urine test, so doctors would always follow up with a blood test (for accuracy purposes). When I decided to have a child, my doctor whipped out the very same brand of urine test that I used. So, I'm guessing there isn't much difference these days.

A urine test is fairly accurate but can really only be used to see if a woman is pregnant or not.

A serum test (blood) is more accurate and in addition to showing "yes" or "no", it can also help pinpoint the date of conception and potential due date of a birth.

It is possible to have a positive urine test and a negative blood test or vice versa. If you think you are pregnant, I recommend the blood test. It's called a Beta HCG Quatitative.

EMT