I think that’s a dire indictment of the education system, but we need to make stuff for the people we have, and a quarter of them can’t read the test.
A subreddit where users post positive or probably positive pregnancy tests.
Pregnancy tests generally measure hCG concentration in urine, early in the pregnancy concentrations are low and the test line will be very faint if visible at all. It's only later on in the pregnancy when the line will become more visible.
Pregnancy also involves a lot of emotion, hope & fear, in combination it's not that surprising that a portion of people misread pregnancy tests.
A quick example of two positive tests side by side https://i.redd.it/llw9fmn6dxk51.jpg
Even worse, sometimes the reaction is so strong that there is a "dye stealer" effect, where the test line steals the ink from the control line. See for example here: https://i.redd.it/skdynwwi6ll51.jpg (Notice how the line is on the "wrong" side)
No wonder the misread rate is so high indeed...
Those are false negatives in the machine.
Source on that? I've only seen 1% reported for lab testing of paper strip.
Which is, high as it is, another surprise! I wonder how that happens.