SyagLchochma and The little I know: I’m sure almost everyone believes that one should get tested (at least I hope) However, you dont have to know what you are a carrier for. Doing your hishtadlus could very well mean having the blood test and going though an organization like Dor Yesharim to see if both sides are compatible.
On the flip side, I always had this question: When someone does check to see if both the girl and boy are compatible, wouldnt this be considered a lack of bitachon? Then again, we cant just sit back and tell ourselves that ‘its ok to marry someone even if we are both carriers’ if we have the tools to prevent sick children or miscarriages or children dying at a young age. ???