Which thyroid function pattern is typical of primary hypothyroidism?

Which thyroid function pattern is typical of primary hypothyroidism?

• A. Low TSH with low free T4
• B. Elevated TSH with high free T4
• C. Low TSH with high free T4
• D. Elevated TSH with low free T4

Answer: (D)

Primary hypothyroidism occurs when the thyroid gland itself can’t produce enough thyroid hormone. Because the body’s feedback system detects low hormone levels, the pituitary increases TSH stimulation in an attempt to boost the thyroid. The result is a high TSH level with a low free T4 level, which is the classic pattern for this condition. This differs from central (pituitary or hypothalamic) hypothyroidism, where TSH is low or inappropriately normal even though T4 is low, and from hyperthyroidism, where TSH is suppressed and T4 is high.

Primary hypothyroidism occurs when the thyroid gland itself can’t produce enough thyroid hormone. Because the body’s feedback system detects low hormone levels, the pituitary increases TSH stimulation in an attempt to boost the thyroid. The result is a high TSH level with a low free T4 level, which is the classic pattern for this condition. This differs from central (pituitary or hypothalamic) hypothyroidism, where TSH is low or inappropriately normal even though T4 is low, and from hyperthyroidism, where TSH is suppressed and T4 is high.