What is the reference range for TSH?

What is the reference range for TSH?

• A. 0.2-4.0 mIU/L
• B. 0.5-5.0 mIU/L
• C. 1.0-3.0 mIU/L
• D. 2.0-6.0 mIU/L

Answer: (B)

TSH reference range is the interval in which healthy adults are expected to fall when measured with a standard assay. It reflects the normal pituitary response to thyroid hormone levels. The range around 0.5 to 5.0 mIU/L is a widely used adult reference interval in many clinical laboratories, so it serves as a practical cutoff for interpreting thyroid status. Values above this range often indicate hypothyroidism (the pituitary raises TSH to try to stimulate the thyroid), while values below suggest hyperthyroidism (thyroid hormones suppress TSH). Remember that exact ranges can vary by assay, population, age, and pregnancy, but 0.5–5.0 mIU/L is the commonly accepted reference for adults in many contexts.

TSH reference range is the interval in which healthy adults are expected to fall when measured with a standard assay. It reflects the normal pituitary response to thyroid hormone levels. The range around 0.5 to 5.0 mIU/L is a widely used adult reference interval in many clinical laboratories, so it serves as a practical cutoff for interpreting thyroid status. Values above this range often indicate hypothyroidism (the pituitary raises TSH to try to stimulate the thyroid), while values below suggest hyperthyroidism (thyroid hormones suppress TSH). Remember that exact ranges can vary by assay, population, age, and pregnancy, but 0.5–5.0 mIU/L is the commonly accepted reference for adults in many contexts.