Confused about Shippen's Estradiol Numbers

[Guest guest]

I have been avidly reading Dr. Eugene Shippen's book, " The Testosterone

Syndrome. " His chapter on estrogen is enlightening but also confusing. At

pages 55-57, he refers to the estradiol levels of various men in the range

between 20 and 58 ng/dL. He suggests that good numbers are around 20 or 30.

Those numbers are consistent with the healthy levels I've seen reported here and

elsewhere. However, the units are wrong! Here, we talk about healthy levels

being around 20 or 30 pg/mL.

1 ng/dL = 10 pg/mL

Therefore, an estradiol level of 30 ng/dL is actually 300 pg/dL, ten times too

high! Is this an error in Shippen's book, or is there something else going on?

Can different assays differ from one another by a factor of 10?

I'd really appreciate some help understanding this.

Thanks, CH