Ultrasound shows pregnancy but urine and blood test negative

I've had a few eptopic pregnancies and recently started fertility pills. I haven't had a period since the end of October but that's not completely abnormal for me.
I've been having some weird symptoms so I went to the doctor. The doctor did an ultrasound and discovered what he believed was an early pregnancy in my uterus. He took urine and blood and both test came back negative. The doctor is convinced this is a pregnancy but can't explain why the tests were negative. Is it possible to be pregnant but the tests show negative?

[Elaine Brown, MD]

Hi!
If you were my patient, I would have to advise you that I don't believe it is possible to have a viable pregnancy with negative tests.  Something is wrong with this picture, and probably it is the ultrasound.  I suppose there could be a non-viable pregnancy.
Hope it works out.  A second opinion in a case like this is not a bad idea.
Good luck!
Dr B