I'm going to do my best to give as much info as I know about different brands of pregnancy tests.
The most sensitive pregnancy tests
First and foremost; rightfully earned...
Genzyme OSOM Pregnancy test cards, combo or regular
Here's why: Genzyme pregnancy tests can detect levels of hCG in quantities as little as 2mIU (yes that is 2) at a 20 minute read time. This is supposed to be specified for serum but the Genzyme HCG tests can detect as little a 5miu in urine. Never ever an evap line; I know some things sound to good to be true but I assure this is true. These test are amazing; period.
Point and case: the first tests is my Genzyme test taken at 8dpo the second is my Equate taken at 10dpo
Fact Plus blue dye +-
Here's why: Fact plus was 3 times as dark as my equate on 10dpo, no questioning the line, even DH saw it. Fact plus is supposed to good at picking up h-hCG also.
Blue dye and may develop evaps after the time limit; I've never experienced this but I don't use them that often.
The + line starts to fade pretty quickly.
Dollar Tree pink dye cassette type
Here's why: Affordable and sensitive. These have been known to detect as early as 8dpo.
They can leave nasty evaps
First Response early results / Answer early
They claim to be sensitive enough to test 5 days before your missed period Approx 11dpo. They are incredibly reliable if you have a line you are pregnant evaps are pretty much unheard of.
Early lines can be extremely faint, sometimes very easy to miss. It makes the test hard to read and sometimes even needs to be put up to light or dried to see a faint positive result. This can lead to the woman believing she is not pregnant when in fact she is.
That's all for now.