How reliable are HPTs?

[FarawayWe]

Hi!

Please help. AF is six days overdue and I did two HPTs, one yesterday afternoon and one first thing this morning and they are both negative.

This morning I had faint nausea and definite dizziness.

My cycle is really regular, mostly 28 days with the occasional four-day delay but never six days!

Why would a HPT be negative? Could it be a chemical pregnancy that is delaying AF?

I am going mad, especially since we have been TTC for 12 years (!) with 9 failed IVFs...

As far as I know HPT's can't really give a false positive due to the pregnancy hormone needed to do the test, however they CAN give a false negative if the hormone present is not strong enough for the test to read. I'd wait a few more days. A doctor apparantly can tell from a blood test, but mine just told me to get a HPT as it's just as accurate.

FIngers crossed for you.