Guest Author - Jim Lowrance

People who are experiencing symptoms they suspect to be related to a possible thyroid disorder and those who have already been diagnosed with hypothyroidism and are being treated for it often ask which thyroid blood tests are best for them. Often Doctors will use the TSH test (Thyroid Stimulating Hormone) to both diagnose thyroid disorders and to monitor the treatment of patients on thyroid hormone therapy. Is TSH the only test that is actually needed? I feel TSH-only is not always sufficient in diagnosing thyroid disorders despite it's sensitivity because it cannot detect thyroid autoimmunity. It also does not always correlate well with the actual T-3 and T-4 levels in patients with other things that may be a factor in causing their thyroid disorder such as pituitary gland failure (source of TSH).

I believe TSH, Free T-3 and Free T-4 are the best thyroid blood tests to have ordered when a patient is being monitored for thyroid hormone therapy. Once these have been retested for the first two or three follow-ups to see where the patient's levels fall and to make sure the T-3 and T-4 correlate well with the TSH level, then testing TSH-only is usually sufficient afterward. When a patient has been replaced with thyroid hormone to a proper level, follow ups may only be needed every few months, twice a year or even once a year if the patient seems to remain stable on the replacement hormone without fluctuations in symptoms.

When people are being tested to diagnose any possible thyroid problems, I believe these same three tests listed above plus tests for thyroid antibodies, should also be ordered. These are the tests that detect an autoimmune process going on that results in both damage and inflammation in the thyroid gland.

If the symptoms a patient is having are those of hypothyroidism, the TPO and TG antibodies should be added and if the symptoms are those of hyperthyroidism, these plus the TSI antibodies should be tested for (usually present with Graves' Disease). This is because hyperthyroid symptoms can be caused by Hashimoto's thyroiditis when in early stages it causes "Hashitoxicosis". This is an intermittent and usually temporary phasing into hyperthyroidism, which is followed by a steady progression into hypothyroidism.