5 Thyroid Patterns That Wont Show up on Standard Laboratory Tests
Copied with the kind permission of Dr Chris Kresser.
Unfortunately misdiagnosis is common in the management of hypothyroidism. If you go to a doctor with hypothyroid symptoms, youll simply be given replacement hormones without any further inquiry into the cause of your condition.
Even worse, if you have hypothyroid symptoms but your lab tests are normal, youll be told youre fine. If you insist youre not, you might be sent home with an antidepressant, but no further clue about the cause of your symptoms.
The problem with this approach is that thyroid physiology is complex. The production, conversion and uptake of thyroid hormone in the body involves several steps. A malfunction in any of these steps can cause hypothyroid symptoms, but may not show up on standard lab tests. Its incorrect and even negligent to assume that all cases of hypothyroidism share the same cause and require the same treatment. Yet thats exactly what the standard of care for hypothyroidism delivers.
In this article Ill present five patterns of thyroid dysfunction that wont show up on standard lab tests. If you have one of these patterns, your thyroid isnt functioning properly and you will have symptoms. But if you go to your conventional doctor, youll be told theres nothing wrong with your thyroid.
A standard thyroid panel usually includes TSH and T4 only. The ranges for these markers vary from lab to lab, which is one of two main problems with standard lab ranges. The other problem is that lab ranges are not based on research that tells us what a healthy range might be, but on a bell curve of values obtained from people who come to the labs for testing.
Now, follow me on this. Who goes to labs to get tested? Sick people. If a lab creates its normal range based on test results from sick people, is that really a normal range? Does that tell us anything about what the range should be for health? (For more on the problems with standard lab ranges, watch the great presentation by Dr. Bryan Walsh below.)
Problems with Modern Blood Chemistry – Dr. Bryan Walsh
The five thyroid patterns
1. Hypothyroidism caused by pituitary dysfunction
This pattern is caused by elevated cortisol, which is in turn caused by active infection, blood sugar imbalances, chronic stress, pregnancy, hypoglycemia or insulin resistance. These stressors fatigue the pituitary gland at the base of the brain so that it can no longer signal the thyroid to release enough thyroid hormone. There may be nothing wrong with the thyroid gland itself. The pituitary isnt sending it the right messages.
With this pattern, youll have hypothyroid symptoms and a TSH below the functional range (1.8 3.0) but within the standard range (0.5 5.0). The T4 will be low in the functional range (and possibly the lab range too).
2. Under-conversion of T4 to T3
T4 is the inactive form of thyroid hormone. It must be converted to T3 before the body can use it. More than 90% of thyroid hormone produced is T4.
This common pattern is caused by inflammation and elevated cortisol levels. T4 to T3 conversion happens in cell membranes. Inflammatory cytokines damage cell membranes and impair the bodys ability to convert T4 to T3. High cortisol also suppresses the conversion of T4 to T3.
With this pattern youll have hypothyroid symptoms, but your TSH and T4 will be normal. If you have your T3 tested, which it rarely is in conventional settings, it will be low.
3. Hypothyroidism caused by elevated TBG
Thyroid binding globulin (TBG) is the protein that transports thyroid hormone through the blood. When thyroid hormone is bound to TBG, it is inactive and unavailable to the tissues. When TBG levels are high, levels of unbound (free) thyroid hormone will be low,leading to hypothyroid symptoms.
With this pattern, TSH and T4 will be normal. If tested, T3 will be low, and T3 uptake and TBG will be high. Elevated TBG is caused by high estrogen levels, which are often often associated with birth control pills or estrogen replacement (i.e. Premarin or estrogen creams). To treat this pattern, excess estrogen must be cleared from the body.
4. Hypothyroidism caused by decreased TBG
This is the mirror image of the pattern above. When TBG levels are low, levels of free thyroid hormone will be high. You might think this would cause hyperthyroid symptoms. But too much free thyroid hormone in the bloodstream causes the cells to develop resistance to it. So, even though theres more than enough thyroid hormone, the cells cant use it and youll have hypothyroid not hyperthyroid symptoms.
With this pattern, TSH and T4 will be normal. If tested, T3 will be high, and T3 uptake and TBG will be low.
Decreased TBG is caused by high testosterone levels. In women, it is commonly associated with PCOS and insulin resistance. Reversing insulin resistance and restoring blood sugar balance is the key to treating this pattern.
5. Thyroid resistance
In this pattern, both the thyroid and pituitary glands are functioning normally, but the hormones arent getting into the cells where theyre needed. This causes hypothyroid symptoms.
Note that all lab test markers will be normal in this pattern, because we dont have a way to test the function of cellular receptors directly.
The five patterns above are only a partial list. Several others also cause hypothyroid symptoms and dont show up on standard lab tests. If you have hypothyroid symptoms, but your lab tests are normal, its likely you have one of them.
Not only do these patterns fail to show up on standard lab work, they dont respond well to conventional thyroid hormone replacement. If your body cant convert T4 to T3, or you have too much thyroid binding protein, or your cells are resistant, it doesnt matter how much T4 you take; you wont be able to use it.
Unfortunately, if you have one of these patterns and tell your doctor your medication isnt working, all too often the doctors response is to simply increase the dose. When that doesnt work, the doctor increases it yet again.
As I said at the beginning of this article, the key to a successful treatment is an accurate diagnosis. The reason the conventional approach fails is that it skips this step and gives the same treatment to everyone, regardless of the cause of their problem.
The good news is that, once the correct diagnosis is made, patients respond very well to treatment.