TSH (thyroid stimulating hormone) is a pituitary hormone, measured directly in blood, that drives thyroid hormone output. Practitioners use it as the most sensitive single screen for primary thyroid dysfunction, and to decide whether free T4, free T3 or antibodies are worth adding. Biotin supplements, time of day and recent illness can all shift the result, so timing should stay consistent between tests.
| Test type | Measured in a blood sample |
|---|---|
| Measurements required | TSH only |
| Sample and collection | Blood draw at a collection centre |
| Preparation | If your practitioner has requested the Baseline Health Check, fast for 8 to 12 hours before a morning collection (water is fine). |
| Turnaround | 3 to 5 business days |
| Available through | Thyroid Function Tests, part of the Baseline Health Check. Also in: Full Body Health Check, Weight Insight Panel, Weight Management Test, Female Hormone Health Test, Perimenopause Test, Menopause Test. |
| Pricing | Included in the $99 Baseline Health Check |
| Results | Returned in the Vively practitioner platform, beside your client's other markers |
What are the TSH reference and optimal ranges?
| Typical lab reference | Vively optimal | |
|---|---|---|
| Adults | 0.5 to 4.0 mIU/L | 1.0 to 2.5 mIU/L |
Labs differ, so read the result against the range printed on the client's report (RCPA guidance); some labs use a lower limit of 0.4 mIU/L. The optimal range guides follow-up and does not apply in pregnancy or to adults over 70.
Check a client's TSH result
Enter the value from your client's lab report to see where it sits against the typical lab range and the Vively optimal range.
A guide only, not a diagnosis. One result is a starting point: read it with symptoms, history and a repeat test. Labs differ, so check the result against the range on your client's report. Nothing you enter is stored or sent.
How do you arrange TSH testing through Vively?
- Get verified. Practitioners with a recognised qualification or membership (ATMS, NHAA, ANTA, Dietitians Australia, NSA, CMA or Ahpra registration) can request free practitioner access.
- Choose a panel. Log in to the practitioner platform and pick a panel that includes TSH, or build your own. It is included in the $99 Baseline Health Check.
- Client collects. Your client collects at a partner collection centre, with their request on their phone or printed.
- Review results. Results come back to you in the practitioner platform, beside your client's other markers, ready for the follow-up consult.
Which Vively panels include TSH?
Log in to the practitioner platform to view a panel in full, or build and save your own from 100+ tests and panels.
- Baseline Health Check74 markers across 11 lab groups$99
One fasting blood draw.
Full Blood CountUrea, Electrolytes & CreatinineLiver Function TestsCalcium, Phosphate & MagnesiumLipid StudiesDiabetes & Glycaemic StudiesIron StudiesThyroid Function Tests+3 moreLog in to view this panel - Log in to view this panelWeight Insight Panel8 markers · Heart & metabolicPrice on sign-up
- Female Hormone Health Test17 markers · HormonesPrice on sign-up
Two blood tests timed to the cycle, to show how hormones shift across it.
Log in to view this panel
Why does the optimal range sit there?
Our 1.0 to 2.5 mIU/L band sits inside the 0.5 to 4.0 mIU/L lab range, excluding the upper zone that early autoimmune thyroid disease inflates.
The US National Academy of Clinical Biochemistry (2003) reported that more than 95% of rigorously screened people without thyroid disease have a TSH below 2.5 mIU/L.
The 20-year Whickham Survey found the risk of later hypothyroidism rose with TSH above 2 mIU/L, most clearly when thyroid antibodies were positive.
TSH rises with age. The TRUST trial (2017) found no symptom benefit from treating mild TSH elevation in adults aged 65 and over. Pregnancy uses trimester-specific ranges.
What should TSH be read with?
- HighHigh TSH, low free T4
Primary hypothyroid pattern that needs GP review.
- ContextTSH 4 to 10 mIU/L, normal free T4
Subclinical hypothyroid pattern; repeat in 6 to 12 weeks and raise thyroid antibodies with the GP.
- LowLow TSH, high free T4 or free T3
Hyperthyroid pattern; refer promptly, especially with palpitations or weight loss.
- LowLow or normal TSH with low free T4
Possibly a pituitary (central) cause or recent severe illness; needs GP review.
What can affect a TSH result?
- Biotin supplements, which can falsely lower TSH on some immunoassays
- Time of day: TSH peaks overnight, so keep retest timing consistent
- Acute illness and recovery from it (TSH can dip, then rebound above range)
- Levothyroxine, amiodarone, lithium, high-dose glucocorticoids and dopamine agonists
- Pregnancy, the postpartum year, and high-dose iodine or kelp supplements
When should you refer the client to their GP?
- TSH above 10 mIU/L, or any TSH above range with a low free T4
- TSH below 0.1 mIU/L, or a low TSH with palpitations, tremor, weight loss or heat intolerance
- Any abnormal TSH in a client who is pregnant or trying to conceive
- Low or normal TSH with a low free T4 (possible pituitary cause)
- A new neck lump, goitre or difficulty swallowing
How should a client prepare for a TSH test?
Copy or print this to send to your client.
Preparing for your TSH test
- If your practitioner has requested the Baseline Health Check, fast for 8 to 12 hours before a morning collection (water is fine).
- Book a morning collection, and keep a similar time for retests, as TSH changes through the day.
- Pause any biotin supplement (often found in hair, skin and nail formulas) for at least 2 days before your test.
- If you take thyroid medication, have your blood taken before your morning dose and take it straight afterwards, unless your doctor has told you otherwise.
- Take your pathology request to any of 4,000+ collection centres. Bring it printed or on your phone.
- Keep taking prescribed medicines as usual unless your doctor tells you otherwise.
- Results usually take 3 to 5 business days and come to your practitioner. Book your results appointment for after that.
How do practitioners use TSH with clients?
While TSH sits between 2.5 and 4.0 mIU/L, iodine and selenium intake, sleep, alcohol and smoking are reasonable to address, with a retest in 3 to 6 months. Avoid high-dose iodine or kelp products without GP input, since excess iodine can push TSH either way.
TSH FAQs
Can a naturopath, nutritionist or dietitian order TSH through Vively?
Yes. Add it to a client panel on the Vively practitioner platform. It is part of Thyroid Function Tests in the $99 Baseline Health Check, and is also in Full Body Health Check, Weight Insight Panel and Weight Management Test. No account yet? Request free access.
Should I add free T4 and free T3 to every TSH?
No. TSH alone is a sound first screen when the client is well and not on thyroid medication. Add free T4 when TSH sits outside 1.0 to 2.5 mIU/L, symptoms are strong, or a pituitary problem is possible. Free T3 mainly helps when TSH is low, or when restrictive eating or heavy training is in the picture.
How long should a client stop biotin before a TSH test?
At least 2 days for typical supplement doses, and 3 days or more for high-dose products of 5 mg and above. Biotin interferes with streptavidin-based immunoassays and can produce a falsely low TSH. Ask the client to check hair, skin and nail products and multivitamins, and to confirm the pause with their GP if biotin was prescribed.
What does a TSH of 3.5 mIU/L mean in a client with fatigue?
It is inside the 0.5 to 4.0 mIU/L reference range but above the Vively optimal range of 1.0 to 2.5 mIU/L, so it does not confirm a thyroid problem. Check free T4, review iodine and selenium intake, sleep and alcohol, and retest in 3 to 6 months. Add thyroid antibodies via the GP if the value keeps climbing.
Why does TSH sometimes look high a few weeks after an illness?
TSH can dip during acute illness and then rebound above range during recovery, so a high value soon after being unwell may not reflect true thyroid disease. Repeat it once the client has recovered, ideally at the same time of day. A TSH that stays high with a low free T4 needs GP review.
References
- Royal College of Pathologists of Australasia. RCPA Manual: Thyroid stimulating hormone.
- Baloch Z, et al. Laboratory medicine practice guidelines: laboratory support for the diagnosis and monitoring of thyroid disease. National Academy of Clinical Biochemistry. Thyroid. 2003.
- Vanderpump MPJ, et al. The incidence of thyroid disorders in the community: a twenty-year follow-up of the Whickham Survey. Clinical Endocrinology. 1995.
- Stott DJ, et al. Thyroid hormone therapy for older adults with subclinical hypothyroidism. New England Journal of Medicine. 2017.
- US Food and Drug Administration. The FDA warns that biotin may interfere with lab tests. 2017.