In a patient with Hashimoto's thyroiditis, the diagnostic test is likely to reveal:

BTSC Staff Nurse 1 August-2025

Medical & Surgical Nursing

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Appeared in: BTSC Staff Nurse 1 August-2025

Explanation

Hashimoto's thyroiditis is an autoimmune disorder where the body's immune system mistakenly attacks the thyroid gland.
The most specific and common diagnostic marker is the presence of antibodies against thyroid peroxidase (TPO), an enzyme involved in thyroid hormone production.
Over 90-95% of individuals with Hashimoto's thyroiditis test positive for TPO antibodies, making it a hallmark of the disease.

Option A: The absence of TPO antibodies makes a diagnosis of Hashimoto's thyroiditis highly unlikely, as their presence is the key feature of this autoimmune condition.
Option B: In Hashimoto's, the damaged thyroid gland produces insufficient hormones (low T4), prompting the pituitary gland to release more TSH to stimulate it. Therefore, TSH levels are typically elevated.
Option D: Hashimoto's thyroiditis leads to progressive thyroid gland destruction and hypothyroidism (an underactive thyroid), resulting in low, not high, levels of T4 hormone.

Clinical Relevance

Nursing practice connection: Use the key finding related to Diagnostic laboratory findings in Hashimoto's thyroiditis to guide bedside assessment, documentation, and the next nursing action.
Nurses play a crucial role in educating patients about the nature of Hashimoto's as a chronic autoimmune condition and the need for lifelong monitoring and hormone replacement therapy.
Accurate diagnosis via antibody testing helps differentiate Hashimoto's from other forms of hypothyroidism, guiding appropriate long-term management and patient counseling.
What if? If a patient presents with a goiter and symptoms of hypothyroidism but has negative TPO antibodies, the nurse should anticipate further investigations for other causes, such as iodine deficiency, drug-induced hypothyroidism, or rarer infiltrative diseases.

How to Approach the Question

First, identify the core concept of the question: the diagnostic features of Hashimoto's thyroiditis.
Recall the pathophysiology of the disease. Hashimoto's is the most common cause of hypothyroidism in iodine-sufficient areas and is an autoimmune process.
Analyze the term 'autoimmune'. This implies the presence of antibodies against the body's own tissues. In this case, the thyroid gland.
Evaluate the options based on this pathophysiology. The presence of an antibody marker is the most direct evidence of an autoimmune process.
Consider the hormonal feedback loop. In primary hypothyroidism (thyroid failure), the pituitary gland increases TSH to stimulate the failing gland, leading to high TSH and low T4.
Eliminate options that contradict the expected state of hypothyroidism (e.g., high T4) or the known feedback mechanism (e.g., low TSH).

Concept Tested & Keywords

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E6 Medicine Harrison 22e Part 2 pp. 934-936, 930-932