Blood Drug Testing

Why a blood test rather than a urine test to determine pregnancy?

My sister has always had a urine test at the doctors to see if she was pregnant. This was the same for her 3 children. Now on her 4th she has to have a blood test. Why is this? Is it because blood tests are the new thing and can determine results quicker.

Public Comments

1. blood test are 100% accurate
2. Yep
3. A blood test is a little more sensitive in detecting pregnancy. My doctor just used a urine test to confirm my pregnancy, but then at my first real check up I had my blood work done to check the HCG levels.
4. Blood test are More reliable also they may be wanting to check her HCG levels in her blood.
5. Sometimes it will not show in a urine test if it is early in pregnancy, a blood test is the sure way to find out!
6. you can pick up preg hormones sooner in a blood test. also, it's doctor preference - did she switch doctors? some are happy with just the urine test.
7. If she went to the doctor when she was more than 12 weeks pregnant a urine test is not as reliable as earlier on in pregnancy. That does seem odd though. Most doctors would give you a urine test if you haven't taken a test yourself. Then you are usually just refered to the midwifery team. Why didn't she ask?!
8. Yes, blood tests are a lot more accurate! I had 2 pee tests done and they were negative but I KNEW I was pregnant so I had a blood test done and it was positive. Sometime the hormonal levels in the urine is not high enough to be detected by a urine test, but blood tests are a lot more sensitive.
9. Her doctor may just want to confirm that she is pregnant, as the blood test pick the hcg hormone up much earlier than the urine pregnancy test. It could be that she is having symptoms and the upt was negative and just to make sure he is performing the hcg quant, which will also tell how many weeks along she is. Sometimes if doctors do the first sonogram and do not visualize a yolk sac then they will do whats call serial quants which is 2 blood test 48 hours apart. and this help to rule out ectopic pregnancy. Good luck, Hope this helps.
10. Well, blood is thicker than water...!
11. Blood tests are used to make sure all of the nutrients are in the mother's blood...making sure she doesn't become anemic or other things because being pregnant that can happen. So basically just to take care of the baby and mother.
12. Blood tests determine results sooner and longer. HcG is the human growth hormone and is detectable earlier in the blood than in the urine. It's also detectable longer as HcG tapers off and is no longer as detectable in urine after about 12 weeks.
13. blood tests are usually more accurate that's why!
14. Blood test are quantitive HCG tests they tell the exact amount of HCG in the blood stream my doc. never gave me a pee test. He always did blood work I would tell him I got a positive HPT and he would do blood work to check the levels also with the HCG test they check progesterone levels. Just because it says positive on the pee test you can't determine the health of the pregnancy without doing blood test they can pick up on problems most early miscarriages( before 6 weeks) and ectopic pregnancies will show up on blood test because the levels will be low. At some point you sister had blood work done early on in all her previous pregnancies. It's just what they do.
15. yeah and they are more accurate
16. She has to get this done to check the hcg levels and also it's results are far more accurate
17. blood test can measure how much of the human hormone is in your blood so its more reliable than urine i would imagine which just tests to see if its there