TSH
Thyroid-stimulating hormone
TSH is produced by the pituitary gland and signals the thyroid to produce hormone. It is usually the initial blood test used to assess suspected primary thyroid dysfunction.
Complete Thyroid Testing
Thyroid blood testing can include TSH, free T4, free T3 and thyroid antibodies. Testing can be arranged without a family doctor requisition, with the panel tailored to your concerns, previous results and testing priorities.
A personalized approach
Build a thyroid panel around your needs
TSH is an important starting point, while free thyroid hormones and antibodies provide different information about thyroid function and autoimmunity. Dr. MacLeod reviews the available options with you and recommends a panel based on your history, symptoms, previous testing and preferences.
- 1
Understand your priorities
Symptoms, previous results, medications, pregnancy status and the thyroid markers you want investigated are reviewed together.
- 2
Choose the markers
The requisition may include TSH, free thyroid hormones, antibodies or other related blood tests based on your needs.
- 3
Interpret the pattern
Results are considered together and compared with the laboratory's reference intervals, not interpreted as isolated numbers.
Core thyroid function tests
What the main markers measure
Each test describes a different part of the relationship between the pituitary gland, the thyroid and circulating thyroid hormones.
FT4
Free thyroxine
T4 is the principal hormone released by the thyroid. Free T4 measures the portion that is not bound to proteins and is available to tissues or for conversion to T3.
FT3
Free triiodothyronine
T3 is the more biologically active thyroid hormone. Free T3 is particularly useful in some evaluations of hyperthyroidism, but it is not required in every assessment of hypothyroidism.
Thyroid antibodies
Markers of autoimmunity
Antibody results can help identify an autoimmune cause of thyroid disease. They do not, by themselves, measure thyroid function, the amount of thyroid damage or the severity of a person's symptoms.
TPO antibodies
Thyroid peroxidase antibodies are commonly associated with autoimmune thyroid disease, particularly Hashimoto thyroiditis.
Thyroglobulin antibodies
Thyroglobulin antibodies are another marker of thyroid autoimmunity. Their significance depends on the reason for testing and the other thyroid results.
Antibody testing is not required for everyone and repeat measurements often do not add useful information once thyroid autoimmunity has been established.
Understanding results
Patterns matter more than a single number
Laboratory reference intervals are specific to the testing method and population. Results are interpreted as a pattern and in the context of symptoms, health history and factors that may affect the measurement.
TSH above range + FT4 below range
A biochemical pattern consistent with primary hypothyroidism.
TSH above range + FT4 within range
A pattern described as subclinical hypothyroidism. Follow-up depends on the degree and persistence of the change, symptoms and clinical context.
TSH below range + FT4 and/or FT3 above range
A biochemical pattern consistent with hyperthyroidism or thyrotoxicosis that requires assessment of the cause.
Results that do not follow an expected pattern
Medication, supplements, acute illness, laboratory interference and pituitary conditions are among the factors that may need to be considered.
High-dose biotin supplements can interfere with some thyroid laboratory tests. Medication and supplement use should be reviewed before blood collection; medications should not be stopped unless specifically instructed.
Selecting additional markers
When broader testing may be considered
These circumstances may support looking beyond TSH alone. The available markers can be reviewed together when planning your panel.
- Previous thyroid results that were abnormal, borderline or inconsistent
- Persistent thyroid-related symptoms that require further clinical assessment
- A personal or family history of thyroid disease or autoimmune conditions
- Ongoing symptoms while taking thyroid medication
- Fertility, pregnancy or postpartum concerns, where interpretation is different
- Fluctuating thyroid levels or suspected pituitary disease
Private testing in Nova Scotia
How the testing process works
A family doctor or specialist referral is not required. Dr. MacLeod helps you select the thyroid markers you want to investigate and reviews the cost before collection.
- 1
Consultation and planning
Your concerns, previous results, health history and preferred testing scope are reviewed.
- 2
Requisition and collection
A private laboratory requisition is provided. Test costs depend on the selected markers and are confirmed before proceeding.
- 3
Results and follow-up
The results are reviewed together, with recommendations based on the findings and the limits of what the tests can establish.
Laboratory testing ordered through a naturopathic doctor is not covered by MSI. Some extended health plans may cover naturopathic appointments, but laboratory coverage varies.
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Related Testing
Frequently Asked Questions
Do I need a doctor's requisition for thyroid testing?
You do not need a family doctor or specialist referral. As a naturopathic doctor, I can provide a private laboratory requisition after reviewing your concerns, previous results and the thyroid markers you want assessed.
Can I request a complete thyroid panel?
Yes. TSH, free T4, free T3 and thyroid antibodies can be discussed when building your panel. I will explain what each marker measures, recommend a testing scope based on your history and previous results, and review any additional thyroid tests you would like considered.
Is thyroid testing covered by MSI?
Laboratory testing ordered through a naturopathic doctor is not covered by MSI and is paid privately. Test costs depend on the markers selected and are reviewed before the requisition is completed.
How should I prepare for thyroid blood testing?
Preparation depends on the tests and medications involved. Please provide a complete list of medications and supplements, including biotin. Do not stop medication unless you have been specifically instructed to do so. Any timing or fasting instructions will be discussed before collection.
What does a positive thyroid antibody result mean?
A positive antibody result can support an autoimmune cause of thyroid disease, but it does not by itself show how well the thyroid is functioning, how severe symptoms should be or whether treatment is required. It is interpreted with TSH, thyroid hormone levels and the clinical history.
Plan Your Thyroid Testing
Book an initial consultation to review your concerns, previous results and the thyroid markers you would like assessed.
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