What are the chances of a blood test for pregnancy showing a false negative?
I had to go on Primolut for three weeks to stop a three week period, I was only on 5mg and was told to expect a period a few days after stopping it. It is now three weeks after stopping, I haven't had my period for 6 weeks. Last week I went to the doctor who did a pregnancy test, I also had a blood test done to rule out pregnancy. They both came back negative. On the day after the blood test I noticed some spotting, hardly anything, just a little bit of pink. I heard people have spotting sometimes when they are pregnant, could it have just been un noticed? Or could this have been like a period, but not? I'm confused. The doctor assured me the blood test was a definite measure (though I have heard of a case where it wasn't) but I need to know the likelyhood that it could have been a false negative!
Thanks in advance.
Filed under Pregnancy Tests by on May 1st, 2010. Comment. 
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Comments on What are the chances of a blood test for pregnancy showing a false negative?
blood tests are 99%accurate so im going to say that they are write at saying negative
You would only get a false neg. if you had them run the test to early. It sounds like you are having hormonal problems to begin with. If you still don’t have a period in a few weeks have your doctor re-test.
False negatives are extremely rare and would only be the result of some sort of lab error or mixup in what they tested for.
They will be looking for hCG in your bloodstream. If the level is over 5 but under 25 the result will come back undetermined, try again, because the pregnancy wouold only be a few days old and the embryo would not have implanted yet. If the result is under 5, then you are definitely not pregnant, or you would have only conceived in the last 48 hours or so prior to testing.
If you doubt the test get another one.