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Are Blood Tests More Accurate Than Urine Tests at Detecting Pregnancy?

Blood Tests to Determine Pregnancy

Pregnancy blood tests, also known as pregnancy serum tests, are created to measure the amount of human chorionic gonadotropin, or hCG, in the bloodstream to determine if a woman is pregnant. Within 10 days of fertilization, this hormone will be evident in the bloodstream, as the placenta will begin releasing it almost immediately after conception. There are two primary pregnancy blood tests. These include the quantitative blood test, which measures the exact concentration of hCG in the blood, and the qualitative test, which will simply indicate if hCG is present.

At What Point Can a Blood Test Determine Whether or Not a Woman is Pregnant?

Blood tests are able to detect pregnancy about 7 to 12 days after conception, making them a better option than most at home pregnancy tests. Unlike home pregnancy tests, they can also determine the level of hCG in your blood. This is particularly useful information for your doctor because it can help reveal information about specific problems commonly experienced during pregnancy. If you ever suspect that you are pregnant because you’re experiencing tenderness of the breasts, pelvic pain, irregular spotting, delayed menstruation, or vomiting, a blood test must be performed to determine whether or not you’re pregnant.

How Accurate is a Blood Test Compared to a Urine Test at Determining Pregnancy?

Due to recent research, it is now believed that blood tests are more accurate than urine tests when it comes to accurately determining pregnancy. According to research from the Scientific Assembly of the American College of Emergency Physicians, about six percent of pregnancies that are reported negative from urine testing come back positive with blood testing. The researchers involved in this study did not expect this result, as they believed that blood and urine pregnancy tests had comparable accuracy.

Additionally, researchers at Henry Ford Hospital examined 662 women who received both urine and blood testing for hCG. Out of the 102 negative results received, six women who tested negative with a urine test were then shown to be pregnant through blood testing. Five of the six women in this group had hCG levels ranging from 11 to 97 mU/ml, a level that is expected during the first month of pregnancy.

While researchers are always wary to claim that false negative numbers such as those reflected in the study are expected, blood pregnancy tests are now used for all women at Henry Ford Hospital who are less than four weeks past their typical menstrual period. As a result, it can be concluded that blood tests are in fact more accurate than urine tests at detecting pregnancy.

What is Meant by the Pregnancy Blood Test Results?

Healthy pregnancies reflect normal hCG levels throughout the entire pregnancy. During the first trimester, it is expected that human chorionic gonadotropin (hCG) levels increase to then decrease throughout the remainder of the pregnancy. Testing is regularly done throughout the first trimester to determine whether or not hCG levels are rising as expected because if they don’t, something might be wrong. Once a child is born, a miscarriage occurs, or an abortion is performed, hCG levels are expected to be at zero once again.

Are Blood Pregnancy Tests Reliable?

The reliability of the results are highly dependent on the lab, methodology, and technique being used for the blood tests. In general, blood tests are more accurate than home pregnancy tests, which have an accuracy level of about 97 percent. However, it’s important to note that blood tests might be more accurate, but not always more sensitive.

  • anonymous

    what’s best? the quantative or the qualitative? because i’m running 3 months delay and got serum(qualitaive type) last 2 weeks and the result was negative. I’ve read some articles and some forums that they still got pregnant even they still got negative result in the blood/serum test. I’m confused. Thanks.

  • earthsmagic

    Typically a quantitative blood test is looking for an increase in the levels of hcg. They are typically done when some sort of fertility intervention is done, like an iui or ivf. The qualitative test will show whether or not the hcg hormone is detectable in your system. It is very uncommon, but not totally unheard of for the pregnancy tests to come back negative for many months. If you are concerned, you might want to do the things you would do if you were pregnant (eat healthily, don’t drink or do drugs, stop smoking and take a prenatal vitamin) until 1) your doctor finally gets a positive pregnancy test, 2) your period finally shows up, or 3) your doctor finds another reason for your period not arriving.

  • 1stpregnancy

    will the blood test determine how far along i am?

  • http://www.earthsmagic.com/ Vickie B.

    Typically, you will only get a qualitative test which is basically a yes or no answer. There really isn’t a way to find out how far along you are until you get an ultrasound.

  • Christy T

    Okay I am having a lot of issues here. I had my son three years ago and my obgyn said I had polycystic ovarian syndrome. I have had normal periods every month since Sept 2012. My period is about two months late and I have taken six test that all resulted in a false pregnancy. I have been cramping like I will be starting my period any moment and nothing has happened. that has gone on for a month or so, I also get very nausea every night around the same time 7;30 to 8:00p.m. I am not real sure what I should do ?

  • haley

    Oh dear.

    I am so confused I am positive I am pregnant. My stomach and body have been going thru changes like none I have ever experienced. I’m going for a blood test today. Hopefully it is not all in my head. :(((

  • Brittany

    Will my doctor order a blood test just to ease my mind or do they only order them if you are having issues?

  • http://www.babyhopes.com/ Vickie B.

    The only way to find out is if you call your doctor’s office and ask them.

  • gina

    I had a blood test on Aug 26,2013, and it came back negative. Today on Aug 30,2013, i happen to take 2 hpts and they came back positive. Im really confused..

  • http://www.babyhopes.com/ Vickie B.

    You should really call your doctor to get another blood test or to find out why that might be. Blood tests are not infallible. Maybe they performed the test too early.

  • jaira lee

    What’s the percent of a blood test being accurate?

  • Paige Lasley

    I am confused and feel as if I’m going crazy. I had an ectopic preg and had it treated with 2 shots of methrodroxite. I am sure that the baby is dead and gone, but I have gained 13 lbs since the death. No change in diet or exercise habits. I saw something about a woman who have birth after being told she miscarried. I feel as though I’m going to give birth next month even though having negative HPTs… I feel like I’m going crazy :’(….

  • http://www.babyhopes.com/ Vickie B.

    You really need to go and see your doctor about this so some tests can be performed. An ultrasound should show definitely if you are pregnant or if something else is going on.

  • Gemini

    Think maybe u should get an ultrasound done that way the doctor can rule out if all these symptoms r jus hormonal r u would b takin baby’ first pic

  • Liza

    I have had no period since augest of 2013 i feel movement in my uteris area i also have been having symptoms of pregnacy have had negative pregnacy tests and i am scared that there could be someting else going on with my reproduction organs what should i do i am going to get blood work done for pregnacy if pregnat i have not had any prenatle care at all

Last modified: March 2, 2014

The information provided here should not be considered medical advice. It is based on the average experience of women trying to conceive and may not be what you may be experiencing. It's not meant to be a replacement for any advice you may receive from your doctor. If you have any concerns about your cycle or our ability to get pregnant, we advise you to contact your doctor.