High or Low TSH? What Your Thyroid Test Really Means

A high or low TSH is a common finding on lab test reports. Learn what this all means for you.

In this video, Dr. Kevin Lowe explains how to interpret a TSH blood test and what high, low, or even normal TSH levels may mean. You will learn how TSH interacts with free T4 and T3, and how these patterns can help identify hypothyroidism, hyperthyroidism, subclinical hypothyroidism, and central hypothyroidism. A high TSH often suggests hypothyroidism, while a low TSH may point toward hyperthyroidism—but thyroid test results are not always that simple. This video explains why TSH should sometimes be interpreted together with free T4, symptoms, medications, thyroid antibodies, pregnancy status, and the broader clinical picture.

Topics covered include:

• What TSH measures

• High TSH and hypothyroidism

• Low TSH and hyperthyroidism

• Subclinical hypothyroidism

• Central hypothyroidism

• Why a normal TSH does not always exclude thyroid disease

• How TSH and free T4 are interpreted together

• When abnormal thyroid results may require further evaluation

Understanding your TSH result can help you ask better questions and have a more informed discussion with your healthcare professional. This video is for educational purposes only and is not a substitute for personal medical advice, diagnosis, or treatment: https://youtu.be/dFLZJfc17fc