Why even the free T3 is NOT an accurate measurement alone

[Guest guest]

(Below comes from Dr. Lowe. Though he concludes at the end that

testing the free T3 is very helpful, more important is HOW YOU FEEL,

or as he puts it: " the patient's physiological and clinical

responses to treatment " Janie)

I personally don't believe that measuring the free T4, free T3, or

any other circulating hormone level, is the most effective clinical

approach. My belief is based partly on the the studies of Escobar-

Morreale and colleagues in Spain.[1][2] Their study results make one

thing clear: Circulating free T3 and T4 levels don't allow us to

accurately predict the T3 concentration in the cells of most

tissues. The evidence suggests that there is simply too much

variability between different tissues in the same patient. Moreover,

there's too much variability between the tissues of different

patients. Even more difficult is accurately predicting the

physiological and clinical effects of different circulating free T3

and T4 levels. Again, there's simply too much variability to allow

accurate predictions.

was right when, long ago, he wrote that circulating levels of

hormones don't measure what's most important—how the patient's

tissues are responding to a dosage of thyroid hormone. Our regimen

involves multiple measures of how tissues are responding to a

particular dosage, repeated at short intervals in a highly

systematic way. Our model of assessment is taken from behavior

modification, in which I was trained in the early 1970s. We know

from hundreds of trial runs that we can precisely control the

metabolic status of most patients only by using these multiple

measures of tissue response. We adjust each patient's dosage until

these measures tell use we've achieved normal tissue metabolic

status—regardless of what the patient's circulating hormone levels

are. I concede that you can do some fairly good tweaking by using

free T3 and T4 levels. But still, if the patient's tissue responses

aren't carefully assessed, the clinician isn't focusing on what's

most important—the patient's physiological and clinical responses to

treatment.

http://www.drlowe.com/QandA/askdrlowe/dxthyrd.htm