[Lotus]

Picograms or Picomoles- hey I didn't invent the damn thing, I interpret the ranges. 

http://www.hemingways.org/GIDinfo/hrt_ref.htm
 
or 

online conversion:

http://www.endmemo.com/medical/unitconvert/Estradiol.php


E2 ref range for male

10-40 pg/mL



E2 ref range for premenopausal women 15-350 pg/mL


Endo's are reluctant to go over 250 pg/mL (low in my opinion, it's a start though).