My guess for those who have been TTC for awhile (especially via IUI, etc.), the need to know exactly what the numbers are doing can be both reassuring and sometimes necessary (for those with previous m/c, ectopic, PCOS (?), etc.). If I spent tens of thousands of dollars on reproductive assistance, I can only imagine what you've already been through to get to that point, trusting a HPT would be hard-- beta blood tests can tell you if the numbers are doubling, etc.. But, that's not me so I'm just guessing-- anyone TTC'd with IUI and want to chime in, etc.?
Funny, but the one test I declined last time was gest diabetes! If you consented to this, I highly doubt that was the only test that was done. You would have had an "OB panel" as well....and much earlier.
It's a good idea to have a base line done-- meaning a full "OB panel
" that includes things like uric acid & platelets, and iron so you know later on if you get a funky reading, if what was "normal" for you.
This also tests for blood type and rh, WBCs, RBCs, rubella titers and etc. Does that ring a bell?
Hope that helps!