Hyperthyroidism

• Often seen in conditions like Graves’ disease (an autoimmune hyperthyroid state).

Thyroid Hormone Overproduction

• May be due to autonomous thyroid nodules.

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Hypothyroidism

• Common in Hashimoto’s thyroiditis (autoimmune destruction) or post-thyroidectomy patients.

Congenital Hypothyroidism

• In infants, low T4 can adversely affect development if untreated.

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Infancy

• Thyroid hormones are critical for brain development; screening is standard for newborns.

Adolescence & Adulthood

• Hormonal fluctuations and autoimmune thyroid disorders are common.

Elderly

• Subclinical or overt hypothyroidism is more frequently seen, potentially complicating other chronic illnesses.

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Thyroid Function

• Common Thyroxine (T4), Free Thyroxine (FT4), Free Triiodothyronine (FT3):
  These markers measure the overall thyroid hormone production and the bioavailable (active) fractions. While Common T4 reflects total hormone levels (both bound and free), FT4 and FT3 specifically indicate the unbound, active hormones that drive metabolic processes.
  
  
• Thyrotropic Hormone (TSH):
  This pituitary hormone regulates thyroid hormone synthesis through a negative feedback mechanism. Elevated or suppressed TSH levels provide insight into thyroid function and help direct further evaluation of thyroid disorders.
  
  
• Thyroxine Binding Globulin (TBG):
  TBG is the main protein binding thyroid hormones in the blood. It influences the proportion of hormone that remains free versus bound, affecting the interpretation of Common T4 compared to FT4 and FT3 levels.
  
  
• thyreoglobulin;calcitonin; tumerous marker thyreoglobulin:
  These markers focus on thyroid tissue activity and neoplastic surveillance.
  
  
  
  • thyreoglobulin reflects the functional activity of thyroid follicular cells.
  • When used as a tumour marker (tumerous marker thyreoglobulin), it helps monitor for residual or recurrent differentiated thyroid cancer following treatment.
  • calcitonin, secreted by the thyroid’s C cells, is particularly valuable in detecting medullary thyroid carcinoma.

Together, these markers offer a comprehensive view of thyroid gland function, regulation, and tissue integrity, integrating hormonal activity with diagnostic tools for thyroid cancer surveillance.

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