what is the accuracy of urine pregnancy test done at hospital?first day of my last period was on 26 june 2011.now i have tiredness,feeling of fullness in the breast,slight fever,some pimple like on my right breast,head ache.last time my duration of menstrual cycle was 40 days.yesterday the urine test done at hospital was negative.do i have to do serum hcg test?weight 61kg.height 5'2