hashimoto's disease does not show up on blood test
Patients with reflux and Alzheimer's were found to have lower levels of T3 in esophagus and brain tissue than normal controls. Both groups tested normal on routine blood tests. For some patients with hypothyroidism, the TSH levels may not rise in the blood. I see this frequently too. The TSH will be perfectly normal or even low due to a variety of mechanisms. Routine tests then will be unable to detect it. Thyroid panels are too limited. A more comprehensive test would include looking beyond TSH to total T3 and T4, free T3 and T4, Reverse T3, and antibody levels commonly found with Hashimoto's disease (the most common cause of low thyroid function).