Blood test vs HPT

[caligal77]

If i had what i believed to be implantation bleeding (from what i've read) and the HPT was negative would a blood test come out negative also? In order to get a accurate result in blood or urine would i have to be technically late first for my period?

[AnnieBrooke]

The blood test is more sensitive than the urine test, and even it (the blood test) will not pick up anything until a certain point.  It is easily possible to have a negative blood test as late as 8 or 9 days after ovulation -- the egg floats around a while (up to 7 days) before implanting in the uterus, and then it needs two days for the hCG to show up in the bloodstream of the mother.  I wouldn't trust either a blood test or a urine test until day 11 or 12 after ovulation, at the EARLIEST.  You're better off to wait until day 14 after ovulation, especially with a home test.  Otherwise if you get a negative you won't be able to trust that it is accurate.