Don't know who you are referring, but, if you are talking about moi, what I said was this:
--The LCMS is the best technology.
--The LCMS range for estradiol changed dramatically from what I can tell.
--We now have little data, due to this range change, for what values of LCMS estradiol reads are low and high and, in particular, which ones will lead to osteopenia / osteoporosis.
Again, I am completely pro-LCMSMS, but I am just asking for you guys to look for guidelines out there for the above as I have not seen any.
Basically, my point is this: a test is useless if you have no research data to go with it. From what I can tell, this new methodology is bumping down estradiol reads by 50-100%, which makes it very difficult to interpret.
In fact, I'll ask you the question: if you have a read of 28 pg/ml with LCMS, what would you do? Under the old way of thinking, you'd be thinking "that is perfect." Now, with the new test, you are actually near the top of the range.
So we just need some docs / researchers / LabCorp to help us understand how to use it imo.
Let me know what you think.
No, it's not you at all. You have been one of the advocates for driving the awareness here and that's fantastic. The one thing I would qualify from your post above is that based on what I've read, while the reference ranges have indeed changed, this doesn't change what numbers are optimal vs. not. The LC/GC/MS method is just more accurate at detecting E2 in the lower range. We still need to be shooting for the same numbers, just using the better test.
My understanding from the studies I've read, including the Endocrine Society study that's been the most revealing, is that the LC/MS methodology is by its very nature the most sensitive and accurate, due to its immunity from interference by other steroids, mainly CRP.
Here are a couple of more interesting excerpts. The first study is perhaps the most interesting because it studies AIs (even though it uses gas chromatography vs. liquid, but MS is used in tandem.Superiority of gas chromatography/tandem mass spectrometry assay (GC/MS/MS) for estradiol for monitoring of aromatase inhibitor therapyhttp://www.ncbi.nlm.nih.gov/pubmed/17588628
"Levels of estradiol were lower when assayed by GC/MS/MS compared to RIA under all conditions...the degree of suppression with the aromatase inhibitors as detected by RIA was 58% versus >89% by GC/MS...these results suggest that most RIA methods detect cross-reacting estrogen metabolites and yield higher measured levels than GC/MS/MS
. Several pharmacological and clinical considerations suggest that GC/MS/MS should become the preferred method for monitoring aromatase inhibitor therapy
."Clinical applications of LC-MS sex steroid assays: evolution of methodologies in the 21st century
Department of Laboratory Medicine and Pathology, Mayo Clinic
Department of Pathology, Heartlands Hospital, Heart of England NHS Foundation Trust, Birmingham, UK
"...As testing demand increased, they were displaced by automated immunoassays. These offered better throughput and precision, but suffered worse specificity problems. Moreover, agreement between different immunoassays has often been poor and they are all compromised by a limited dynamic measurement range. To overcome these problems, LC-MS/MS methods have been developed and validated for quantitation of sex steroids. These (LC/MS) methods reduce interferences, provide better specificity, improve dynamic range, and reduce between-method bias