Doctors are ignoring their patient's symptoms as long as their blood work comes back in the "normal" range. However, the blood hormone levels may not always yield a correct diagnosis, with both false positive and false negative results.
Secretion of TSH (thyroid stimulating hormone) is influenced by many factors other than the negative feedback inhibition by thyroxine (T4) or triiodothyronine (T3). Levels of TSH are very often the sole parameter by which doctors diagnose hypothyroidism. According to the report, "symptoms are not considered a criterion by some authorities ... the clinical features of hypothyroidism seem to have been relegated to the status of historical curiosities."
A 20 year follow-up study published in BMJ in 1995 showed that TSH concentrations above 2 mU/l are associated with an increased risk of hypothyroidism. Half of the population fall into this category and need to be concerned about the optimal functioning of their thyroid gland.
Relation Between TSH and Risk of Hypothyroidism
The equation to describe the relation between the probability of developing hypothyroidism and the serum thyroid stimulating hormone concentration is: ln {P/(1P)}=b0+b1 ln TSH+0.027 age (+1.79 if antibody positive). b0=5.02, b1=0.30 if TSH < 2 mU/l b0=6.38, b1=1.97 if TSH > 2 mU/l
The equation to describe the relation between the probability of developing hypothyroidism and the serum thyroid stimulating hormone concentration is:
ln {P/(1P)}=b0+b1 ln TSH+0.027 age (+1.79 if antibody positive).
b0=5.02, b1=0.30 if TSH < 2 mU/l
b0=6.38, b1=1.97 if TSH > 2 mU/l
Another confounding factor is that changes in TSH, T4, and T3 concentrations during systemic illness are poorly understood and therefore thyroid function tests cannot be interpreted in these patients. Since rates of systemic illness are so high, especially in those with hypothyroidism, a high percentage of patients undergoing thyroid testing would fall into this category.
BMJ 2000; 320: 1332-1334
Naturally oriented clinicians have been saying that conventional thyroid testing is inaccurate for many years. Diagnosing and treating hypothyroidism has been promoted by performing assessing body temperature. Broda Barnes and others recommend this technique. I used to do this but found it cumbersome and inconvenient.
The TSH has been around for 30 years. The original reference range of 0.5-4.2 was compiled on 29 patients!
So the bottom line here is that if your TSH is greater than 2.0, your are at a clearly increased risk of developing hypothyroidism and need to be careful of this in the future. You can review my diagnosis article for more information.
A more sophisticated form of blood testing, that I rarely find that endocrinologists perform, seems to work much better. It involves actual measurement of the free hormones, which is NOT the standard thyroid test that is done on nearly everyone. There are a significant number of people who will have a normal TSH and yet have depleted free hormone levels. This indicates a relative failure of the pituitary and hypothalamus. An important point to recognize when addressing the thyroid though is to understand that the thyroid will frequently stop working well when it has to overcompensate for compromised adrenal glands. Normalizing the adrenal glands first will frequently help the thyroid gland return to normal. I believe this is best done with salivary hormone panels and my favorite company is Bio Health Diagnostic (800-570-2000).