why TSH isn’t the only marker to assess thyroid function
Understand why the standard lab test used to assess thyroid function in Australia is inadequate. Get expert advice from naturopath Rebecca Gunning on how best to assess and maintain a healthy thyroid.
Thyroid Dysfunction: Beyond the Norm
Are you struggling with weight issues, fatigue, or gut problems, despite being told that your thyroid labs are normal? It's time to delve deeper into understanding the complexities of thyroid health.
In the past five years, research has shed new light on reference ranges for thyroid investigations, compelling the medical community to re-evaluate their approach. It is now becoming accepted that relying on TSH alone as a thyroid marker is insufficient.
Recent studies recommend routine monitoring of TSH and T4 every 3-6 months, accompanied by a reassessment of the reference ranges that the laboratory sets out. A suggested median range for TSH falls within 1.0-2.5, which challenges the current Australian reference range of 0.5-4.5.
But thyroid health is not solely determined by TSH and T4 levels. To fully comprehend the intricacies of this vital gland, we must also consider the roles of T3, reverse T3, and thyroid antibodies.
T4, an inactive hormone, must undergo conversion to T3 to exert its effects on the body. Metabolic rate, heart and digestive function, muscle control, brain development, and bone activity are all influenced by T3. Neglecting to assess T4 conversion to T3 means missing a pivotal aspect of thyroid function and its correlation with overall bodily communication.
Further complexities arise when T4 is redirected towards reverse T3 production. Elevated levels of reverse T3, commonly observed during periods of inflammation, stress, or fasting, bind to T3 sites in the body. Reverse T3 fails to deliver the positive effects associated with active T3, leading to symptoms of low thyroid hormones.
To complicate matters even further, elevated thyroid antibodies raise concerns about inflammatory thyroid conditions, malignancies, and systemic inflammatory issues, all of which contribute to thyroid-related symptoms.
Reference:
- PMID: 28536577
- PMID: 28680357