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

  • chantelleL

    About a month ago I was having abdominal pain and wasn’t sure it was I went to my family doctor he told me it sound like a beginning of an ulcer..a couple data later went to emergency the pain was so bad it went to my stomach they did a urine test nothing come up they did a blood test and I was positive.. The pains I get are so bad to deal with that today found our I got the flu can a pregnancy test just be wrong saying that I am but not really just for having the flu… Also to boot I got my period full blown to I was 9 days late but still got my normal period of light heavy then light again..is this something to worry about??

  • shawna

    So i dont know what to do im having all the signs and symptoms of being pregnant and im 11 days late but whats crazy is i had tubal procedure done. I took a hpt and it was negative but somethings not right. Should i go get a blood test to see if im pregnant

  • Nat

    Go to the hospital – there is the possibility that you have an ectopic pregnancy and you need to get that checked out. I was bleeding for two weeks with an ectopic ( just thought it was a weird period) and had really bad pains… I would be getting this checked out.

  • Tori-Lynn

    I’m going to start off by apologizing because this might be long because I want to start from then beginning. I am 28 yrs old and have never had a regular cycle ( maybe one to three periods a year since I was eighteen). We recently ( ended 5-9-14 ) had a weight loss competition at my job where I lost about twenty pounds. ( weight loss sometimes causes my period.) The past couple of weeks I have been having headaches, nausea, extreme fatigue, and tender nipples. Also just the past few days I feel a little pressure when I try to sleep on my stomach and have felt a little twinge in the lower left region of my lower abdominal ( more central than left). I have not had a period anytime recently so don’t even know where I should be with that. I went to the dr. last Mon.( 6-16-14 ) for these symptoms and he didn’t even test me for pregnancy but I went straight home and got a negative. I had lab work done last week so I followed up with another appt. today ( 6-23-14 ). This time the nurse gave me a urine test but I’m assuming it was a negative because my Dr. did not even mention it and put me on high blood pressure meds. ( I have never had a problem with my bp or cholesterol, ever ). Needless to say I came home and got another negative. I have never felt the things I have been feeling and I’m not sure if I should take the medicine because it says it could be fatal to a fetus if pregnant. Could it be I might be testing to soon or am I just wanting something so bad my body is playing tricks on me? I do not know what to do. Please feel free to share anything with me. Thank you.

  • Angelia Locklear

    What if you have took 10 to 15 pregnancy test and they are postime and the blood test came out negative. My nipple have milk in them and I am nauseated and my brest are swollen. Any ideas?

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

    Perhaps a second test by the doctor? Or at least further testing to find out what is going on with your system is you are not pregnant.

  • Donnasu Knox

    My sister has hard time conceiving. She tested at home two weeks ago and it was positive but she was in er bleeding two days later. They still cant tell her if she lost the baby . She is going for bloodwork every few days. Her levels are up to 800. What im wondering is if this has happened to anyone out there and what was your outcome? She is on such an emotional rollarcoaster and has been for slmost 2 weeks now.

  • confused

    I have been to my nurse pr

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

    I think you should probably ask them to find out what is causing your issues which would require more testing than the nurse practitioner just feeling your stomach. If you have only missed two periods, if you were pregnant, your baby would not be big enough to create movements on your stomach.

  • monica

    I am very confused and concerned. in july my period was late but when i did get it on the 17th I got a regular period with a medium flow. So I did not worry. I took 3 tests now that i am about 5 days late and they came out positive so i went to the dr and she said if it said positive she would just confirm it by taking blood. The results came back negative! still no period and have this overwhelming sense that i am pregnant. I am very confused.

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

    Sometimes labs make mistakes. If you continue getting positive tests, you need to go back to your doctor. Just treat yourself as if you are pregnant until you can get the dr to listen to you.

  • LuLu

    Hi…

    Im having a problem I did a home test like 3 time and all of them came negative.. but the thing is my last period was 2 Aug 2014, I have cramps, dizziness, and I keep felling tired all the time for the last 3 weeks.
    Today I did another home test but still nothing! What should I do!!

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

    At this point, you should probably go and see your doctor to see if they can figure out what is going on.

  • Nae nae

    Hey I did a test at a health centre it came out positive. So my doctor assign me to go do an ultrasound. When I took it dey wasn’t seeing anything other than something tiny tiny but on the other hand my discharge was brown reddish and I was frighten of losing my baby… Idk what’s wrong and why we not seeing anything on the ultrasound

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

    It depends on how far along you were. Very early pregnancies typically do not show up on ultrasounds very well. Typically they do a scan at 10 weeks to find out how far along you really are.

  • mama H

    I have taken 4 home pregnancy test within the week and all came out positive. Went to the dr. To take urine test and came back negative. 2 of the home pregnancy tests were taken after the dr. Visit and we’re positive. Not sure what to think. I had a miscarriage about a year ago and I am worried it could happen again. I also have recently started metformin for diabetes. Called the dr to schedule an appt. They directed me to leave a message for the nurse. I left a message for her and haven’t heard back. I called this morning. Anxious, worried, and excited!

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

    If your urine tests keep showing up pregnant, then I would ask them to do a blood test. If you had been drinking water or other beverages before you went to the doctor, the level of hcg in your urine could have been diluted below the sensitivity of the test they use. Good Luck!


Last modified: March 2, 2014