Bloods!

We have just been referred for <a href="https://glowing.com/glow-fertility-program">ivf</a> and whilst it’s all going through they want me to do some bloods on cd2 and cd21-25. Now I know the cd21-25 is to look for ovulation but I don’t ovulate until cd25/26 of a 40 day cycle so if I go at 25 it’s not going to show anything is it?!?! What do you think I should do?