What Causes Thyroid Problems? Possible causes include autoimmune conditions, iodine imbalance, thyroid inflammation, certain medications, genetic factors and previous thyroid surgery or treatment. The underlying cause determines the appropriate management approach. How Are Thyroid Disorders Diagnosed? A healthcare professional may recommend: - TSH blood test: Commonly used to assess thyroid function. - Free T4 and sometimes T3 tests: Help evaluate thyroid hormone levels. - Thyroid antibody tests: May help identify autoimmune thyroid disease. - Thyroid ultrasound: Used when a lump, enlargement or structural abnormality needs assessment. - Additional investigations: Recommended when clinically necessary. Not every patient needs every test. The choice depends on symptoms, medical history and examination findings.