Patients Don’t Lie - Thyroid Lab Tests Do

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Patients Don’t Lie - Thyroid Lab Tests Do

 

http://drhotzeblog.netymology.com/2006/05/24/patients-dont-lie-thyroid-lab-tests\

-do/

By Steven F. Hotze, M.D.

 

I have a healthy skepticism of lab tests, based on my own clinical experience

with these tests. The same blood samples from several of my patients have

been sent to different labs for measurement of their thyroid hormone levels, and

the results have varied by as much as 50 percent. The most that can be said

about a lab test is that it is a snapshot of what is going on in the blood at

one moment in time. However, thyroid hormone blood levels vary throughout the

day and their actions are affected by disease processes, prescription drugs,

other hormones that the body produces, and even environmental chemicals.

 

Also, the “normal laboratory range†of thyroid hormones is an arbitrary

value, defined statistically as plus or minus two standard deviations from the

mean. This so-called normal range is as wide as the Grand Canyon. In practice,

it

means that approximately 90–95 percent of the population will always fall

within the normal range. However, I assure you that 90–95 percent of the

population does not feel healthy, well, and full of energy.

 

Not only that, but the arbitrarily defined “normal†value has actually

changed over time. Between 1991 and 2002, the normal laboratory range for the

free

thyroxine (free T4) blood test was lowered by 15 percent, from 0.90–2.00 ng/dl

to 0.76–1.70 ng/dl.

 

What this means is that an individual in 1991 who had a free T4 value of 0.80

ng/dl would have been classified by a conventional doctor as hypothyroid, but

an individual with an identical T4 value in 2002 would be told that her

thyroid function was in the normal range and would be denied treatment. Yet

these

two patients, separated in time by eleven years, likely would have had numerous

symptoms in common—symptoms that are highly responsive to thyroid hormone

replacement therapy.

 

Declining Hormones = Declining Health

 

Leaving aside the problems of conflicting lab test results and variable

definitions of what is “normal,†there is another reason why lab tests

should not

be the sole factor in determining whether an individual has hypothyroidism:

thyroid hormone levels decline with age, with predictable effects on energy and

well-being. It is the relative decline in your thyroid hormone level that

matters, not your level compared to some arbitrarily defined standard.

 

Let’s say that as a healthy twenty-five-year-old, your free T4 level was 1.60

ng/dl—the high end of the “normal†range. By the age of fifty, your free

T4

level might be as low as 0.80 ng/dl—the low end of the “normal†range.

This

represents a 50 percent decline in the thyroid hormone that is available for

use by your cells. Since thyroid hormones enable your cells to generate energy,

is it any wonder that as your thyroid hormone level declines, your energy

level also decreases?

 

If a doctor relied solely on a lab test to evaluate your thyroid function, he

would tell you that your condition is “normalâ€â€”but you wouldn’t feel

normal

with 50 percent less thyroid hormone. To ensure that you have plenty of

energy and feel healthy, your doctor should strive to maintain your thyroid

hormone

level in the range that is optimal for you.

 

This is the approach I take with my patients. Yes, I do perform blood tests,

primarily to measure free thyroxine (free T4) and to determine whether thyroid

antibodies are present. I also look at the total cholesterol and LDL (“badâ€

cholesterol) levels because these are often elevated in patients with

hypothyroidism. However, my primary criterion for diagnosis—and for evaluating

the

effects of treatment—is how the patient feels.

 

If you came to my office with symptoms indicative of hypothyroidism, even

though your thyroid hormone levels might be in the so-called “normal†range,

I

would likely offer you a therapeutic trial of thyroid hormone replacement. I

would start you on a very low dose and then slowly increase this until your

symptoms diminish.

 

An individual with hypothyroidism must be treated gently, like a car on a

cold winter’s day. When you get into a cold car and start the engine, it often

knocks. Cold air comes out of the heat vents. If you gun the accelerator, you

might throw a rod in the engine. Instead, you let the engine warm up slowly and

then take the car on the road. Likewise, in the use of thyroid

supplementation, small doses are prescribed initially and increased gradually

until the

symptoms are relieved. The final dose varies from patient to patient.

 

For a FREE e-Book by Dr. Hotze on Hypothyroidism and Thyroid CLICK HERE.

http://www.drhotze.com/EN/free_ebooks/400.html