Anti-Microsomal/Peroxidase Antibody (Anti-TPO Antibody)

What is it?
Anti-microsomal (or anti-thyroid peroxidase, Anti-TPO) antibodies are autoantibodies directed against thyroid peroxidase, an enzyme found in the thyroid gland. This enzyme plays a crucial role in the production of thyroid hormones.

Clinical Significance:
The presence of Anti-TPO antibodies is often associated with autoimmune thyroid diseases, including:

• Hashimoto’s thyroiditis (Chronic autoimmune thyroiditis) – Most commonly seen with high levels of Anti-TPO, leading to hypothyroidism.

• Graves’ disease – May be present in Graves’ disease, an autoimmune disorder causing hyperthyroidism.

• Postpartum thyroiditis – Temporary thyroid dysfunction occurring after pregnancy.

Normal Range & Interpretation:

• Negative/Normal: Typically <35 IU/mL (may vary by laboratory)

• Elevated Levels: Indicate an increased risk of thyroid dysfunction but do not always confirm disease; further clinical evaluation is required.

Symptoms Associated with High Anti-TPO Levels:

• Fatigue

• Weight gain or loss

• Dry skin

• Hair thinning

• Cold or heat intolerance

• Depression or anxiety

Why is the Test Done?

• To diagnose autoimmune thyroid disorders

• To assess the cause of hypothyroidism or hyperthyroidism

• To monitor thyroid function in individuals at risk of thyroid disease