Is a Thyroid-Stimulating Hormone (TSH) level of 0.982 within the normal range?

TSH Level of 0.982 is Within Normal Range

A TSH level of 0.982 mIU/L is within the normal reference range, which is typically 0.4-4.5 mIU/L, and does not require further evaluation or treatment in the absence of symptoms. 1

Understanding TSH Reference Ranges

• The normal reference range for TSH is typically 0.4-4.5 mIU/L, with slight variations between laboratories 1
• A TSH level of 0.982 mIU/L falls well within this normal range, indicating normal thyroid function 1
• TSH reference ranges are based on statistical distribution across the general population rather than association with symptoms or outcomes 2
• The reference range may be slightly broader in older adults (0.4-5.9 mIU/L for ages 70-79) 3

Interpretation of TSH Values

• A normal TSH indicates euthyroidism (normal thyroid function) with an accuracy of >99% 3
• Subclinical hyperthyroidism is defined as TSH below the lower threshold (usually <0.4 mIU/L) with normal T4 and T3 levels 2
• Subclinical hypothyroidism is defined as TSH above the upper threshold (usually >4.5 mIU/L) with normal T4 levels 2
• Your TSH value of 0.982 mIU/L is neither low nor high, indicating normal thyroid function 1

Factors Affecting TSH Interpretation

• TSH secretion is highly variable and sensitive to several common factors, including:
  • Acute illness
  • Certain medications
  • Time of day (TSH typically peaks at night)
  • Season of the year 2, 4
• A single TSH measurement should not be used alone for diagnosis of thyroid dysfunction 2
• If there were clinical concerns, confirmation would require repeat testing over a 3-6 month interval 1

Clinical Implications

• With a TSH of 0.982 mIU/L, no further thyroid testing is necessary in the absence of symptoms 1
• This value does not indicate subclinical or overt hypo- or hyperthyroidism 2
• There is ongoing debate about optimal TSH ranges, but most authorities maintain the reference interval of 0.4-4.0 mIU/L 5
• Some experts have proposed narrowing the upper limit to 2.0-2.5 mIU/L, but there is insufficient evidence to support this change for clinical practice 5

Common Pitfalls to Avoid

• Overdiagnosis and overtreatment of thyroid dysfunction is common based on single abnormal laboratory values 2
• Avoid initiating treatment based on a single TSH value, especially when it falls within the normal range 2
• Remember that approximately 25% of persons with even subclinical thyroid dysfunction revert to normal thyroid function without intervention 2
• Treating patients with normal TSH values will not lead to benefit and may expose them to unnecessary medication risks 2