Thyroid Stimulating Hormone (TSH) in Serum/Plasma

Why Is This Test Done?

Your doctor may order a TSH test to check for thyroid problems, such as hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid). It’s often the first test used to diagnose these conditions because TSH levels can be sensitive indicators of thyroid function.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before the test if it’s part of a more complex evaluation. Bring any medications you’re taking to your appointment.

What the Results Mean

TSH results can vary based on your health, age, and other factors. High TSH levels often suggest hypothyroidism, while low levels may indicate hyperthyroidism or other conditions affecting thyroid function. Your doctor will interpret results in the context of your medical history and symptoms.

Common Conditions This Test Helps Diagnose

A TSH test can help diagnose or monitor conditions like hypothyroidism (e.g., Hashimoto’s disease), hyperthyroidism (e.g., Graves’ disease), pituitary disorders, and thyroid nodules. It’s also used to check for thyroid hormone imbalances in pregnant women or those with symptoms like fatigue, weight changes, or mood swings.