Low progesterone levels don't really have anything to do with detectability of a pregnancy on a home pregnancy test.
Home pregnancy tests test for the presence of hCG (human choronic gonadotropin), a chemical secreted in blood and urine.
HPTs test for different levels of hCG in the blood, which many people don't know. They're not all alike. Some, like the FREDs (First Response / Early Detection) or FRERs (First Response / Early Results) can detect as little as 50 mIU/ml of hCG, if memory serves (or maybe it's 25, I forget...) versus other HPTs that only detect 100 mIU. In other words, the FRERs are far more sensitive to smaller amounts of hCG, which doubles approximately every 48 hours, so they can tell sooner if you're preggo.
Oh, and as far as the snippy nurse who said that the HPTs were 99% accurate, she's right...accurate for POSITIVE readings, that is. For NEGATIVE readings, they're not so good -- in other words, a positive is a positive is a positive, but a negative does NOT necessarily mean no
It might just mean maybe
-- or not yet detectable. In short, like so many OB nurses, she was full of bushwah.
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