Skip to main content
Free expedited shipping on all orders

TSH test, explained.

A TSH test measures thyroid stimulating hormone, the signal your pituitary gland sends to tell your thyroid how much hormone to make. TSH usually rises when the thyroid is underactive and falls when it is overactive. Many labs use an adult range of about 0.4 to 4.5 mIU/L, and your report prints its own.

What it measures
The signal that tells your thyroid how hard to work
Fasting
Not needed. Ask about pausing biotin first
Who should test
Adults with symptoms or risk factors
In Lab Pass
Yes, every plan, $199 a year

TSH ranges

ResultTSH
Common lab rangeAbout 0.4 to 4.5 mIU/L
US reference population (NHANES III)0.45 to 4.12 mIU/L

Sources: AACE and ATA hypothyroidism guideline (2012), which advises using each lab's own range, and the NHANES III population data. TSH often runs higher with age and differs in pregnancy; your report prints its own range.

Who should test

The USPSTF found too little evidence to recommend for or against TSH screening in adults without symptoms. Thyroid guidelines favor testing when there is a reason to look: symptoms, another autoimmune condition such as type 1 diabetes, a past thyroid problem or neck radiation, a family history of thyroid disease, or medicines such as amiodarone or lithium.

What can throw it off

Biotin, common in hair, skin and nail supplements, can throw off thyroid results, and many labs ask you to stop it at least 72 hours before the draw. TSH also runs higher at night and early morning, and can shift with a recent illness, steroids, pregnancy, older age, or a change in thyroid medicine in the last 6 to 8 weeks. Check with your clinician before stopping any supplement or medicine.

How Sipra reads it

Your Lab Pass reads TSH on its range with a plain language read. For more than TSH, the Thyroid Deep-Dive adds the full thyroid hormone and antibody picture for $69 in most states.

Questions, answered

Many labs use roughly 0.4 to 4.5 mIU/L, but each lab sets its own range, and it can differ with age and in pregnancy. Use the range printed on your report, and ask a clinician where your number falls for you.

Biotin can throw off thyroid results, and many labs ask you to stop it at least 72 hours before the draw. Check with your clinician before stopping any supplement or medicine.

Not by itself. TSH can shift with the time of day, a recent illness, age and some medicines, and a mild result is often rechecked along with free T4. A clinician should read it with your symptoms and history.

The USPSTF found too little evidence to recommend for or against routine screening in adults without symptoms. Testing is more often advised with symptoms or risk factors. Talk with a clinician about whether it makes sense for you.

TSH is part of every Lab Pass, which costs $199 a year in most states and reads 130+ biomarkers from one blood draw. The plan renews each year at the then current price until you cancel, and we email you before it does. Insurance is not billed, and Sipra lab panels are generally HSA and FSA eligible, so check with your plan administrator.

Other tests in Lab Pass

General information, not medical advice. A licensed physician signs your lab order; talk with your own clinician about what a result means for you.