Years before blood tests – TSH, FT3 and FT4 – were developed to evaluate the function of your thyroid, doctors used the reflex response of the Achilles tendon to determine the status of thyroid function.If a patient had “thyroid symptoms,” such as dry skin, dry hair, cold, constipation, hair loss and inability to lose weight, low thyroid function was suspected. The patient was asked to kneel on a bench or table, and the ankle reflexes were tested. If found to be sluggish, the diagnosis of hypothyroidism was made and desiccated thyroid medication was given until the reflexes improved and/or the patient’s symptoms resolved. This reflex, called the Woltman Sign, is most easily observed at the ankle tendon (Achilles) but can also be evaluated at other sites where reflexes are routinely tested.To learn more about the Woltman sign, go here.NiTek International embraced the simplicity of the Woltman Sign and developed a device called a Thyroflex. The in-office evaluation uses the brachioradialis tendon, near the elbow, to check the rate and caliber of the reflex response. The Thyroflex provides a pain-free, needle-free, cost-effective measurement of thyroid function with an accuracy of 98.5 to 99% when compared to laboratory testing.Why is the Brachioradialis reflex used?The brachioradialis reflex is used because the tendon is easy to access and the procedure can be performed while sitting comfortably in a chair. In addition, the Achilles reflex may be an unreliable indicator in some patients, particularly in those with diabetes, some neurological diseases and in the elderly.
How does the test work?
A small strap is placed around your hand. The exact reflex point on the brachioradialis tendon is located and marked with an X. A metallic hammer that is connected to a computer is used to strike the reflex point. The computer measures the time between the strike of the hammer and the upward fleck of the wrist. The longer the time lapse, the more you are in need of additional thyroid hormone.Ideally, it should take 50 to 100 milliseconds for the wrist reflex to occur. If the response time is greater than 150 milliseconds, it is a sign of low thyroid functioning or hypothyroidism. If the reflex response is very fast, less than 50 milliseconds, it is an indication that your thyroid is overactive, or hyperthyroid.The Thyroflex test takes approximately 4 minutes to administer and results are provided immediately. If you are taking thyroid medication, your doctor can make subtle adjustments in your dosage, even if your lab tests are in the normal range. A Thyroflex assessment is actually a deeper determination of thyroid function: It is the only test available that determines how well your thyroid hormones are functioning at the cellular level.