TSH (thyroid stimulating hormone)

Pick Ordered or Not ordered to see the note.

Indicated when

• —Symptoms suggestive of thyroid dysfunction: new fatigue, unexplained weight change, palpitations, heat or cold intolerance, hair thinning, menstrual irregularity, or a palpable goitre [1, 2]
• —Higher-risk groups, even without symptoms: pregnancy planning or early pregnancy, 6 weeks to 6 months postpartum, a personal history of thyroid disease, other autoimmune disease or neck irradiation, or a medication known to affect thyroid function such as amiodarone or lithium [1, 2]
• —Monitoring known thyroid disease or a levothyroxine dose change, checked no sooner than 4-6 weeks after the change [1, 2]

Not indicated when

• —Routine screening of asymptomatic, average-risk, nonpregnant adults as part of a general wellness panel [3, 4]

Why not

Canadian and US bodies differ slightly in how strongly they discourage this: Choosing Wisely Canada advises against screening asymptomatic nonpregnant adults outright, while the USPSTF found the evidence insufficient to weigh benefit against harm rather than issuing a firm recommendation against it [3, 4]. Either way, testing a person with no symptoms or risk factors mainly risks a mildly abnormal, subclinical result whose treatment benefit is unproven, which can prompt more testing or treatment without a clear payoff.

Better first step

Take a focused history and exam for thyroid symptoms and the recognized risk groups, and order TSH when one is present rather than adding it to every visit as routine bloodwork [1].

Typical ND rationale

An ND often includes TSH in a baseline or 'wellness' hormone panel, reasoning that thyroid dysfunction is common, its symptoms (fatigue, weight change, hair thinning, mood or menstrual change) are easy to miss, and it is a cheap, low-risk test worth adding even without one specific trigger.

Ontario coverage & CONO orderability

OHIP status

insured

TSH is listed by name (L341) in the 2026 Schedule of Benefits for Laboratory Services with a standard professional fee, so it is insured when a physician who has clinically assessed the patient orders it. The same test ordered by an ND is patient-paid regardless (Reg. 552 s.22).

CONO orderable

Yes — CONO list #127

CONO list item 127, blood: 'TSH (thyroid stimulating hormone).'

Linked conditions

• Hypothyroidism ↗
• tired ↗

Counselling script

“TSH is the right first test whenever we're genuinely checking your thyroid, so if your symptoms or history put you in that group, I'll order it today. If you're feeling well with no thyroid symptoms or risk factors, adding it as part of a general wellness screen isn't something the evidence supports, so I won't order it just to be thorough. Either way, if a TSH does come back abnormal, I'll add a free T4 on the same sample to sort out what's going on.”

Revisit if

• —New fatigue, weight change, cold or heat intolerance, palpitations, or hair thinning
• —Menstrual irregularity or difficulty conceiving
• —Pregnancy planned or confirmed
• —6 weeks to 6 months postpartum
• —New medication known to affect thyroid function (e.g., amiodarone, lithium)
• —Family history of thyroid or autoimmune disease newly disclosed

References

1. [1]Ontario Association of Medical Laboratories (OAML) (2007). Guideline for the Use of Laboratory Tests to Detect Thyroid Dysfunction (CLP 015). linkolder guidelineTSH alone is the appropriate initial test in most situations; lists the recognized high-risk screening groups and the 4-6 week wait after a dose change
2. [2]American Association of Clinical Endocrinologists / American Thyroid Association (2012). Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. linkolder guidelineSerum TSH is the single best screening test for primary thyroid dysfunction for the vast majority of outpatient situations
3. [3]College of Family Physicians of Canada / Choosing Wisely Canada (2026). Family Medicine: Fifteen Tests and Treatments to Question. linkDon't screen for thyroid dysfunction in asymptomatic nonpregnant adults
4. [4]US Preventive Services Task Force (2015). Screening for thyroid dysfunction: U.S. Preventive Services Task Force recommendation statement. linkolder guidelineCurrent evidence is insufficient to assess the balance of benefits and harms of screening for thyroid dysfunction in asymptomatic, nonpregnant adults (I statement)