Re: Different Laboratories (Lab One Vs Quest)

Nora and Robert kill me. I'm getting dumber just reading this thread. The
answer to your question is yes, different laboratories may test for TSH
using different assays or even different technology altogether. The term
"Normal" is such a misnomer, and should really be referred to as a
"reference" range. People think that if they fall outside that "Normal"
range on one occasion they should be buying a cemetery plot. The
reference range provided by your laboratory comes from testing the TSH
level of a population (random group of people, probably >100) and
recording the results. Some people will have higher levels of TSH and
some will have lower levels. Your laboratory is telling you that compared
to their reference population (your random people off the street, subway,
farm, wherever) your serum tested somewhere near the middle. So, to that
I say...terrific. The fact that Quest uses different reference ranges
should not be a factor for comparison, since the assay performed may well
be a completely different methodology (i.e. chemiluminescence vs. MEIA
vs. RIA). Some methods are more sensitive (some by orders of magnitude!)
but may have more interferences, such as medications,etc. Your
endocrinologist may be expressing concerns over the validity of the
result, given past experiences with that particular laboratory, or that
perhaps repeating the test using a different method might provide a more
probative result, given your medical history or current medications.
Unlike Nora and Robert, your endocrinologist will likely take ALL of this
information into account, not simply one laboratory test result (Shame on
you both!), and provide the best opinion or course of treatment he can.
I'm not sure what led you to seek the help of an endocrinologist, Don,
but I wish you well.

Don wrote:

> I am 31 and male. Last month I had some lab work done through Lab One
> which my insurance pays for 100%. My TSH was high normal and my
> testosterone was low normal. I went to an endo for the first time in
> my life today. He said he did not trust lab one and wanted me to
> repeat the test with another lab. He said something about Quest using
> a TSH reference range of anything over 2.5 as abnormal. My lab one
> report said normal was .35 - 5.5 (My TSH was 3.35.)
>
> Do different labs do testing that can cause different results?
>
> Any advice would be greatly appreciated!