If you regularly check your TSH levels to monitor your thyroid health, it’s recommended to always do it in the morning. Otherwise your results may show a false normal even though you still have low thyroid. As with all the body’s hormones, your thyroid hormones follow a natural daily rhythm, fluctuating throughout the day. One study has estimated that nearly 50 percent of low thyroid patients are not properly diagnosed due to improper testing times. Low thyroid patients' blood hormone levels were tested before 8 a.m. and again between 2 and 4 p.m. Both medicated and unmedicated patients experienced a substantial drop in TSH during the afternoon test. The unmedicated group's TSH measured 5.83 in the morning and 3.79 in the afternoon, whereas the medicated group's TSH was 3.27 in the morning and 2.18 in the afternoon. In support of this finding, a 2004 study revealed that late morning, non-fasted TSH was 26 percent lower in comparison to early morning, fasted TSH. This means skipping an early morning blood draw for a later test could result in a missed diagnosis. The benefit of functional medicine ranges and proper TSH test timing While the timing of your thyroid blood draw may have a significant impact on your results and diagnosis, there is more to the picture. An early morning blood draw may provide more accurate results, yet many doctors still misdiagnose low thyroid because they rely on old-school lab ranges that leave too wide a margin. The old TSH lab range standard still used by many doctors includes results from 0.5 to 5.0 even though new research supports the American Association of Clinical Endocrinologists recommended range of 0.3 to 3.0. In functional medicine we use a narrower lab range of 1.8 to 3.0. This better reflects the range where thyroid patients feel healthy and function well. We also know that testing only for TSH frequently results in a missed thyroid diagnosis. For example, TSH may be within range but other critical thyroid markers are not. It's recommended to run a complete thyroid panel that includes total and free T4 and T3, free thyroxine index (FTI), reverse T3, T3 uptake, and thyroid binding globulins. Inflammation, chronic stress, hormonal imbalances, and many other conditions can lead to low thyroid function. Ordering these added thyroid markers assures better insight into these connections. Always test for autoimmune Hashimoto’s low thyroid In addition to the above tests, if you have symptoms of low thyroid ask your practitioner to also test for Hashimoto’s, an autoimmune disease that attacks and destroys the thyroid and other organs. It's estimated about 90 percent of US low thyroid cases are caused by this autoimmune version of low thyroid. The standard Hashimoto’s lab factors are TPO and TGB antibodies. Every cell in your body needs thyroid hormone, so low thyroid may require medication. However, hormone replacement does not address the autoimmunity at the root of the attack on your thyroid gland. Failing to manage the autoimmunity of Hashimoto’s increases your risk of developing other autoimmune diseases such as pernicious anemia, Type I diabetes rheumatoid arthritis, and others. It also makes it harder to cope with the myriad symptoms. Ask my office how to properly test for low thyroid and manage your thyroid health.