TSH (Thyroid-Stimulating Hormone) Test
A TSH test measures thyroid-stimulating hormone, a signal the pituitary gland sends to the thyroid. It is one of the most common first-line checks clinicians use to help evaluate how the thyroid is working.
About this test
Thyroid-stimulating hormone, or TSH, is made by the pituitary gland, a small structure at the base of the brain. Its job is to tell the thyroid how much hormone to release. Because the pituitary raises or lowers this signal in response to the thyroid's output, TSH acts as a sensitive indicator of the overall thyroid conversation, and that is why it is so often the starting point.
The TSH test is done with a simple blood draw at a patient service center. A phlebotomist collects a sample from a vein, usually in the arm, and the sample goes to the laboratory. No special preparation is typically needed, though people follow any instructions their ordering clinician provides. Results are read by a clinician in the context of symptoms, history, and any other markers ordered alongside it.
Who commonly orders it
People who order a TSH test are often looking into symptoms that can be linked to thyroid activity, such as fatigue, changes in weight, feeling unusually cold or warm, or shifts in mood and energy. Others use it as a routine check, to follow thyroid care over time, or because a clinician has suggested a closer look. It is frequently the first thyroid marker chosen because a single result can point to whether further testing is worth considering.
What this test looks at
TSH sits at the center of a feedback loop. The pituitary gland senses how much thyroid hormone is circulating and adjusts the TSH signal to nudge the thyroid toward making more or less. Because that adjustment tends to be sensitive, TSH often shifts before other markers do, which is part of why clinicians reach for it early.
It also helps to remember what TSH is not: it describes the signal being sent to the thyroid rather than the thyroid's own hormones. That distinction is exactly why a clinician may follow a TSH result with tests that look directly at hormone output.
How it's often used alongside other thyroid tests
TSH is frequently the opening move in a thyroid evaluation. Depending on what a clinician observes and the symptoms a person describes, it may be paired with free T4 to compare the signal against the thyroid's output, or with antibody markers when an immune process is being considered. Read together, these markers offer a fuller sense of the thyroid conversation than any single one of them can on its own.
What to expect at your visit
No appointment is needed. People can walk into a patient service center during open hours, and the draw itself is quick — a phlebotomist collects a small sample from a vein in the arm, and most visits wrap up in a few minutes. Once the laboratory completes its analysis, results are posted to the account, where they can be reviewed and shared with a clinician.
Your results
Results will be emailed securely to you as a PDF.
One-time price · physician order included · no insurance needed
Prefer a fuller panel?
A curated bundle groups this test with the markers clinicians most often review alongside it — often better value than single tests.
Frequently asked questions
What does a TSH test measure?+–
It measures the level of thyroid-stimulating hormone in the blood. This hormone comes from the pituitary gland and reflects the signal being sent to the thyroid rather than the thyroid's hormones themselves.
Why is TSH often the first thyroid test ordered?+–
The pituitary adjusts TSH sensitively in response to thyroid output, so a single TSH result can help a clinician decide whether the thyroid picture needs a closer look with additional markers.
How is the sample collected?+–
Through a routine blood draw at a patient service center. A phlebotomist takes a small sample from a vein in the arm and sends it to the laboratory.
Do I need to fast before a TSH test?+–
Fasting is not usually required for a TSH test, but people should follow whatever preparation instructions their ordering clinician gives, since individual situations vary.
Is TSH ever measured together with other markers?+–
Yes. Clinicians often pair TSH with free T4 or other thyroid markers to get a fuller view. TSH reflects the pituitary's signal, while thyroid hormones reflect the gland's actual output.
How much is a TSH test?+–
$19, paid once at checkout. The price includes the physician's order this test requires and sample collection at any of 2,300+ Quest patient service centers nationwide.