Blood instead of pee?

So I saw this video of a women who already knew she was pregnant prick her finger and dip her blood on a cassette test instead, at first I was like no way, but then hers came back positive! So out of shits and giggles I done one cause of boredom I guess, (wouldn't really recommend just go pee on a stick) 😂 but for the women that have tried this has it been reliable for you? Because I got a clear as day positive and now I'm freaking tf out. (no I didn't hurt myself whilst doing this, was a simple finger prick)