Interpretation of Thyroid Function Tests in Hypothyroidism and Hyperthyroidism

Understanding Thyroid Function

The thyroid gland plays a crucial role in regulating metabolism through the secretion of thyroid hormones. Disorders such as hypothyroidism and hyperthyroidism result from abnormal hormone levels.

Laboratory Findings in Hypothyroidism

Primary Hypothyroidism

• Elevated TSH: Due to insufficient thyroid hormone production.
• Low free T4: Indicates thyroid dysfunction.

Secondary Hypothyroidism

• Low TSH: Caused by pituitary or hypothalamic disorders.
• Low free T4: Reflects reduced thyroid stimulation.

Laboratory Findings in Hyperthyroidism

• Low TSH: Suppressed due to excessive thyroid hormone production.
• Elevated free T4 and T3: Hyperactive thyroid function.

Conclusion

Accurate interpretation of thyroid function tests is essential for diagnosing thyroid disorders and guiding appropriate treatment strategies.