Anyone had - pee test but + blood?

I have had all negative pee test but went to dr today cause I burned my leg. He Knows I'm ttc and asked how it was going. I said we'll I'm 20 days late but all negative test. so he took blood today cause he doesn't want to give me antibiotics till he ran blood work. I told him it was gonna be negative he said we'll lets see just in case.  Anyone ever had negative pee test but postive blood