Hashimoto’s thyroiditis diagnosis

Your provider may test^[14] for Hashimoto's thyroiditis if you feel increasingly tired, have dry skin, a hoarse voice, constipation, or previous thyroid problems.

Hashimoto’s thyroiditis test

A diagnosis of Hashimoto’s thyroiditis is made after detecting elevated levels of thyroid hormone and thyroid-stimulating hormone (TSH) produced in the pituitary gland. Tests may include:

• A hormone test: Some tests can determine the amount of hormones produced by your thyroid and pituitary glands. If your thyroid is underactive, your thyroid hormone levels will be low. Because the pituitary gland is trying to stimulate the thyroid gland to produce more thyroid hormone, your TSH levels will also be elevated.
• An antibody test: People with Hashimoto’s thyroiditis produce abnormal antibodies^[15]. You may have Hashimoto’s disease if a blood test reveals high levels of thyroid peroxidase (TPO) antibodies. However, TPO antibody tests alone won’t necessarily indicate that you have Hashimoto’s thyroiditis.

In the past, people weren't able to detect an underactive thyroid (hypothyroidism) until symptoms were fairly advanced. However, through the TSH test, your provider can now diagnose thyroid disorders much earlier—often before you even notice symptoms. Given the effectiveness of the TSH test, your provider will likely check your TSH level first. Knowing your level of the thyroid-stimulating hormone will also help your provider decide on the right dosage of the medication for you, both when you begin treatment and over time. You likely won’t need other tests to confirm that you have Hashimoto’s thyroiditis. However, if your provider suspects that you have Hashimoto’s thyroiditis but doesn’t find abnormal antibodies in your blood, they may request an ultrasound of your thyroid. Ultrasound images can show the size of your thyroid, as well as other features of Hashimoto’s thyroiditis. An ultrasound can also rule out other causes of an enlarged thyroid, such as thyroid nodules (lumps in the thyroid gland).