quoting Jipí:

I tried µg/mL, but then you get like .00045 or so. ng/mL gives you 4.5, though, and mL is a more customary division of a liter than dL, I think? OTOH, idk medicine.

Actually testosterone is generally measured in ng/dL and estradiol in pg/mL, tho there's a new tendency in labs to regularize it all and just express it in subunits of mol/L. /dL is not uncommon in medicine, for instance you use it for blood sugar and this customarily... it results in prettier numbers, I guess.

Check this: http://en.wikipedia.org/wiki/Reference_ranges_for_blood_tests#Sex_hormones