<s>[INST] Hello Im Joelmy girlfriend, after having 1 week period delay, took a pregnancy test, which resulted positive. However, 2 weeks later she blood-checked in a hospital and the resulted NOT pregnant. Though her period didnt come yet, I wasnt given any clear answer from the hospital, please help! thank you [/INST] Hi, Thanks for writing in.1. Home pregnancy test is by estimating the beta subunit of Chat Doctor in urine. This is positive after 15 days from sex if pregnancy has happened. However, there are some limitations when the result can be false positive and pregnancy has not occurred.2. The blood beta subunit of Chat Doctor estimation is done in the hospital and this is accurate. This is usually a quantitative estimation and not wrong. Therefore, if they have measured beta subunit of Chat Doctor in blood, and it is negative then pregnancy is not a probability and the home pregnancy test is false positive.3. If in doubt then you can go for a transvaginal ultrasound after 6 to 7 weeks from the last menstrual periods and this will most likely show a pregnancy. Please discuss with your doctor in detail and request for an ultrasound scan if required. Please do not worry. </s>