Opk question

McKenzie • 💍 05/2011 👧🏼07/2011 👶🏼🎀 04/2019 🤰#3 due 03/2021

I thought that I read somewhere that you needed to not drink anything and hold your urine for two hours before taking an opk but now I can’t find that source and I’m wondering if that’s true? I just get so thirsty and I’m thinking that if I don’t drink anything for two hours it’s going to be a nightmare lol any advice is appreciated