Life Extension's Advisor Department provided the following:
We at Life Extension understand your concerns andf rustration. We have the same ones when we review scientific studies dealingwith hormones. Unfortunately, hormone testing is problematic due to a lack of standardization across different laboratories. Even within the same laboratory there are different ways (methodologies) to test the same hormone. For example, total testosterone can be tested via ECLIA gen 1 or gen 2(electrochemilluminescene immunoassay) and LC - MS/MS (liquid chromatography tandem mass spec). These issues with hormone testing have lead to frustration among doctors, researchers and us here at Life Extension. We would like nothing more than to be able to provide you with concerete answers, unfortunately we cannot because of the all the variables and lack of standardization in hormone testing as it exist today.
In fact the CDC in the US has been spearheading a program to address issues in hormone testing. However, it is moving along slowly. Here is a link to the program for more details:
This site goes further into the problems and details we all face trying to make sense of hormone results.
Your question of the conversion factor for estradiol is agood one; however, as much as we would like to give you a definite answer, we can't because the conversion factor alone is not enough. It also depends on which lab did the test and what was the exact methodology they used for the your test. There are no conversion factors that take those variables into account.
Thus, the best way we have found over the years is to make educated approximations using the reference range of the lab that did the test.
The LabCorp reference range for estradiol using the Roche ECLIA methodology for men is:
Adult male: 7.6-42.6 pg/mL
The LEF suggested optimal range for this specific test from LabCorp is:
Adult male: 20-30 pg/mLRather than trying to convert it (which doesn’t work well because of methodology differences), take a proportional approach. For example, our optimal range is basically right in the middle ofLabCorp’s reference range for estradiol, give or take a little on each side of the average of 25 pg/ml. Thus, we would suggest targeting the same using the reference range from your lab (not our lab). You should be around the average of your lab’s reference range, give or take a little. This approach is consistent with studies showing that for a man you don’t want estradiol too high or too low.
Is this a perfect approach? Of course not. Do we wish it could be more accurate and precise? Yes, but until such time as all labs start using the same methodologies, units and reference ranges this approach has been the most helpful.