Excerpt from the book - Why Do I Still Have Thyroid Symptoms? When My Lab Tests Are Normal by Dr Kharrazian...
"Hashimoto's Disease and "Normal" Lab Results
Jan - TSH 4.5
Feb - TSH 0.08
Mar - TSH 2.3
April - TSH 3.8
May - TSH 8.7
June - TSH 7.4
July - TSH 1.6
One reason hypothyroidism goes misdiagnosed is because a person with Hashimoto's can present with normal TSH. This graph illustrates the monthy TSH levels of a person with Hashimoto's who is receiving no treatment. As the autoimmune condition fluctuates, TSH levels vary wildly. Using standard lab range of 0.45 - 4.5 this person would fail to be diagnosed. During the month of March the patient's TSH even falls within functional range 1.8 - 3.0. That's why also testing for immune antibodies and evaluating symptoms and history are so vital."