Warning! If your doc provides a written lab order for sensitive estradiol and you go to Quest, they will not give you the sensitive test unless the specific test code is written on the order by your doc. Second time I have been to Quest with a written order and had to battle to get the sensitive test even though it was specifically written on the lab order (but did not have the order code). Quest's rule is that the sensitive test is for only younger than 18 years old (no idea why). Now I always make certain that it is the sensitive test before they draw.