How Soon Can a Blood Test Detect Pregnancy?

Updated on October 6, 2015

When Will a Blood Test Detect Pregnancy Hormones?

Do you think you might be pregnant, but you are not sure about the reliability of the home test you've taken? Or perhaps you want to know now if you're pregnant but it's too early to take a urine test, so you are considering a blood test.

When can you trust the home test and when do you need to take a blood test instead?

There is much to consider when deciding whether or not to get the blood test. How accurate are they? How much trouble and cost are they? How soon can you take one and when will you get the results?

Let's explore.


Accuracy of Pregnancy Blood Test

The blood test has a 99% accuracy rate, so it's almost always accurate. The main reason for this is that a blood test can detect even the smallest traces of the pregnancy hormone hCG, that is if you take the quantitative blood test.

Qualitative vs. Quantitative Blood Tests: The quantitative blood test measures how much hCG you have in your blood. The qualitative test, on the other hand, just gives you a yes or no answer as to whether you're pregnant. The quantitative test is more precise and also helps to determine whether the pregnancy is normal and healthy. There will be increasing amounts of hCG in your system in the first four weeks of gestation but then it begins to taper off, so by measuring these levels of hCG, a doctor can determine whether things are progressing normally.

The Accuracy of a Urine Test

Comparatively, urine tests, or home tests, can be inaccurate 6% of the time.

Reasons a urine test can be inaccurate:

  • Taken too soon.
  • Medications are affecting levels of hCG in your system.
  • Urine cup is dirty.
  • Test kit is faulty.
  • Blood in urine.
  • Protein in urine.
  • Recent miscarriage (so there's still hCG in your system).
  • Ovarian tumor.

Have you tried a home pregnancy test or a blood test?

See results

How Soon Can You Take a Blood Test?

This is another advantage to taking the blood test: You can take it sooner than the urine test. Typically, a urine test won't show positive results until two weeks after conception or the first day after a missed period. In contrast, you can take a blood test and get an accurate result within 7-12 days after conception because it will detect the smallest amounts of hCG.


Things to consider about the pregnancy blood test:

  • Higher cost than a home test.
  • Have to take it at the doctor's office.
  • Have to wait for results.

Pregnancy Blood Test: Time and Money

Another factor that should be considered before taking the blood test is the fact that it is less convenient and more expensive than a home test. The home test is relatively inexpensive and you can pick it up over-the-counter or order online and have your results within minutes of taking the test.

The blood test must be taken at the doctor's office. You have to get there, wait there, go through the procedure, and of course, there's the bill.

How Long Do You Have to Wait for the Results of a Blood Test?

So you've gone to the doctor's office, waited to be seen, and had your blood drawn. Of course, it's not over.

Your blood has to be sent to a lab to be analyzed. How long it takes for them to give you the results varies from lab to lab. It can be as soon as an hour or as long as several days. But a couple of days is a typical waiting period for lab results.



So as you can see, there are many things to consider when you are trying to figure out whether to take the blood test and what to expect from it. It is more expensive and less convenient. You will have to wait for the lab to get results. However, it is more accurate, can detect the slightest bit of pregnancy hormone in your blood, and you can test sooner than you can with a urine test.


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    • profile image

      Katie 2 weeks ago

      I take a pregnancy test at home and the doctor it came back povsitive

      But the doctor did a blood test and it came back negative.

    • profile image

      JENN 3 weeks ago


    • profile image

      Samvia munir 5 weeks ago

      My serum test positive what I do

    • profile image

      glory 2 months ago

      i had unsafe sex 4days after my period,my man pulled out

      now my period is little late and i took urine test twice its positive but am positive that i had no sperm in my V during last sex!i be feeling PMS syndromes for almost 2weeks

      i doubt these tests

      QUESTION....hCG can be detected few days before period???

    • profile image

      Star 2 months ago

      I had blood test done to get my birth control shot started up cause i was a month late and had sex two days previous to blood test. Ive been really nauseous lately is there a chance i could be pregnant

    • profile image

      i am Helen i got pregnant for 5 days carried out blood test but still negative 2 months ago

      I am Helen I got pregnant for 5 days I carried out blood test but still negative

    • profile image

      Lori ward 3 months ago

      I am wondering if I can be pregnant because I took a test and it was negative and I had some light blood and then spoting and then light blood and the spoting again and now nothing is it to soon to take a blood test please let me know

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      Xxxx 4 months ago

      I had my last period May 8th 17, i've had spotting twice, still not had a period, i've done about 8 home pregnancy tests all negative, the doctor has done 2 negative pregnancy tests, i've now been sent for bloods to be done i'm awaiting results. My stomache is bulging now from the top of my stomache, my waist is disappearing and i'm constantly tired and want to eat loads! I just needs to know if i am pregnant cos something is wrong?

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      Mary 4 months ago

      Hi, I had my periods on 23rd of August 2017,had unprotected sex on 28th of the same month and on 2nd of September, I then took emergency pills on 3rd of September and had unprotected sex again the same day after taking the pills.

      What are the possibilities, please help. Can I be pregnant?

      My periods are not regular.

    • profile image

      Special Kay 4 months ago

      I had intercourse on the 21st, 22nd, and the 28th of August. My period was due to come on the 29th of August, but did not show. I waited until August 30th to take a test and it was instantly positive! I took a second one later in the day and it was also positive. Is it possible to have a positive test so soon?

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      Kayla 4 months ago

      I had sex on August the 7th. I then had a blood pregnancy test done with qualities/quantitative serum done on August 13th and got a negative result. If the result were positive would it had of shown up?

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      Xmen 6 months ago

      My Gf is scared whether she is pregnant..her period is almost 2 months late. So we did a normal blood test.. Report is not coming yet.. So I want to know if it can tell if she is pregnant or not??

    • profile image

      DONT KNOW ANYMORE 7 months ago

      HI THERE


    • profile image

      Peanut 8 months ago

      My wife has been spotting for a few days a light red and today she says honey why is it a lil darker that with a lil blood clot, I said I have know idea, so I googled it and it said, if she is pregnant then it's the 1st trimester of being pregnant and don't be scared,she did go and get a blood test like a day ago or so, just waiting to hear back from the doctor's office

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      Larissa 8 months ago

      Hi I went through an iui cycle through ivf I had the trigger and also pregnyl 3 times after getting inseminated I then got my 2 week pregnancy test she said my levels were at 9 so she can't so I'm not pregnant because 5 and under means ur not pregnant but she thinks that my levels might b up a bit cause if the medication I was on. Has anyone has this please let me know

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      Annabel 11 months ago

      My Implannon was in 5 years too long. I had a slight 2-3 day period before Christmas. Before that I was regular 28 days bar one month before the 2-3 days I bled for 3wks. it's now February nd still no period I'm worried the 2-3 days was a show. Done a test two wks ago which was negetive iv had a blood test not checking for pregnancy nd the nurse said nothing. What's going on could I be pregnant?

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      emmza 16 months ago

      hi im 31 years old i not sure if im pregnant i took urine test thats came negative a couple took are from dollar store 1 i took today was a u check from the dollar store and on august the 8 took a clear blue test digtial came negative on 10th took another clear blue negative still havent got my period my period doesnt come regular so not sure but in july period was july 8 and last period was August 5 to august 11 was i even ovualting? back to this part ok had sex august 14 start spotting august 19 a bit pink more red light with a bit brown 1 time i wipe was a chuck of red blood but just one time not even sure if i was ovulating still no period and its september 14 today again period is not regular took a blood pregancy test on sept 15 negative is it still early still no period ? was I even ovualting?

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      lexie 16 months ago

      so I'm 20 and i suspected i was pregnant, i did 2 drugstore tests which were negative (it was too early) and i went to the gynecologist today, she did a vaginal ultrasound and told me i seemed to be pregnant (that there was a lot of fluid which there usually is early in a pregnancy) so she sent me to do a blood test but it came out negative. i'm very confused, i haven't gotten my period yet, could i be pregnant even though the test was negative? I'm only 2 days late on my period and the interaction happen at the 10th of August. Any help anyone? I though i would wait until I'm 7-8 days late and then go to an other gynecologist. could i be pregnant or..? can anyone help me out? i know that blood tests aren't too reliable when it's that early in a pregnancy because you dont have enough of that hormone in your blood yet right? :/ please help I'm stressing out

    • profile image

      Pequena 20 months ago

      I been feeling pregnant for about 2 months now. Symptoms: sore breasts, areolas darkened with small bumps, leakage when nipples are squeezed, dizziness, nauseas, no appetite, visible veins (arms, legs, breasts), headaches, tiredness, bloading, metallic taste, moodiness. Had bleeding lime periods for the passed 2 months. Had urine test and blood work done which all were negative. Saw the doctor and did blood work and tested my prolactin levels and my thyroid, also checked my pituitary gland for anedoma and everything is normal. I'm still having all the symptoms and I don't know what else to do or think. Can anyone help please

    • profile image

      Neha 2 years ago

      I am 22 years old, and a pcos patient!

      I had sex with my boyfriend on 1st jan 2016, I had an ipill after that!

      But we had unprotected sex again ! I googled and chose not to eat ipill again!

      How can I be sure of not being pregnant? Do I need to take a pregnancy test?

    • profile image

      elizabeth 2 years ago

      am 10 days to my menses,can blood test detect if am pregnant?please any help

    • profile image

      Jenn 2 years ago

      Hi i had a question about blood test and pregnancy is it true that sometimes it wont even show then until about a month to two months i ask cause my last period was in aug. And i still havent had my period i had a blood test done an it was negitive is why im asking

    • profile image

      Carlota 2 years ago

      Hi im 4 days late iv taken 2 hpt both negative im having a little dizziness lately and been having cramps should I go get a blood pregnancy test ??

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      Ivone 2 years ago

      Can hCG be detected 3 days after ovulation? Is the 7 to 12 days after ovulation pretty accurate, as in cannot be detected sooner? I had a vaginal ultrasound and doc couldn't tell if i was pregnant so she had me take a blood test, which came back negative. I ovulated around Tuesday (i took the home test) and had intercourse days leading up to ovulation. That's why i ask :)

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      Chrissy 2 years ago

      I have taken 3 tests 10 dpo 13 dpo and 14 dpo and all negative i had intercourse last thursday and started to spot on friday and mow its monday an i have still been only spotting some pink some brown som blood red and a few times with clots. We have not taken any more HPT im nervous and scared to .... My question is can it be my period if im only spotting and there is no blood flow.

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      vicky 2 years ago

      Hi im 10 weeks late with pcos...ive done pregnancy tests n come back negative....I had a hormone blood test last week and got a borderline result today...Iive gotta wait for phone consultation tomorrow to find out what it means.....could it mean im pregnant? As ive been trying for over a year.....

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      laurice 2 years ago

      Scared, I am older and now I am 9 days late. Scared because I have always wanted children. I have been PG once ended with an ectopic pregnancy...HURT BEYOND BELIEVE. Headed to doctor in an hour for blood test, don't want a negative result. Can't talk to anyone I know because I am tired of being disappointed. Praying for +++

    • profile image

      kia 2 years ago

      Hi everyone I had my mirena removed last Friday and me and my boyfriend had been very sexually active for the pad couple of days I have been having lower cramps as well as being very sleepy. I took a pregnancy test it came back negative I an thinking that I might be to early to tell. Any suggestions on why I am have these cramps? Are when to take another test?

    • profile image

      lisa 2 years ago

      I just found out i am pregnant. Took 2 hone test and got blood work done. All are positive. But i am having a dull pain on my, right lower back side. And under my right rib.

      Does antine know if this is normal?

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      steph 2 years ago

      Yes, but it could also be your body adjusting

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      Jordan Yates 2 years ago

      I've taken pregnancy test several times, I have hard and sore nipples , and white in the tips of them, I have a white discharge that I've seen on the internet it's a yeast infection but my friends who have been pregnant say that they only had a white discharge during pregnancy and that a yeast infection is discolored. I have taken 3 test all look to be negative the the most resent I have taken shows negative but if I tilt it or hold a light under the test there is a clear line, but the other two test doesn't have the clear line under the light. I've had cramps and bloating feeling , and some nausea . I resentful had my nexplanon birth control removed from my arm, the doctor said I should have a period in a couple days after it was removed but it's been a month and I've had no period yet! Could I be pregnant?

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      NathaNater 2 years ago

      Nicole, it might be a good idea to see a doctor and see if you can have a blood test done; they are more accurate and reliable.

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      Nicole Franco 2 years ago

      I'm 19 days late on my period i have taken 3 home tests and they are all negative i pee frequently and my breast are really tender to the point to where i can't even lay on them i am a little worried

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      NathaNater 3 years ago

      Good luck, Shai. Sounds hopeful. Hopefully your daughter will soon have a brother or sister.

    • profile image

      Shai 3 years ago

      I've taken 9 first response pregnancy tests all showed a very faint positive I'm Supose to start my period in 3 days I have a drs appt in 2 days so I'm gonna have another test done when I go hopefully I am I have a 3 year old daughter and she needs a brother or sister :) wish me luck

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      NathaNater 3 years ago

      It is safe to take the PPD test if you're pregnant and pregnancy will not affect its results. But it is wise to consult a doctor and tell medical professionals that you think you might be pregnant. Also, one of the routine tests during pregnancy is a blood test for rubella. However, you cannot be immunized if it turns out you're pregnant because it could hurt the baby. So, if you are talking about immunizations, you should not have them done if you think you are pregnant.

      If you had implantation bleeding before and during your missed period, that could be a sign that you are pregnant. The urine tests could be inaccurate, especially if you've had something to drink because then the urine is diluted; it is best to take them in the morning before you've had anything to drink. The blood test is much more accurate, 99% accurate, because it can detect the smallest traces of the pregnancy hormone.

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      beth 3 years ago

      Well I am confused because I am late from my period a week and 2 days and I've taken two hpts and they were negative and went to planned parent hood had pee test it was negative but I truly believe I am pregnant but to early to show I had what I think was implantation bleeding 3 days before my missed period and some throughout when I was sup post to get my period and its been a week since that should I get a blood test. And I am getting a new job and need rubella and rubeolous and PPD done I don't know if that will affect if I am pregnant