What is the appropriate management for a patient with a Thyroid-Stimulating Hormone (TSH) level of 0.92 and unknown Free T4 (FT4) level?

Management of a Patient with TSH 0.92

A TSH level of 0.92 is within the normal reference range and does not require further evaluation or treatment in the absence of symptoms or other clinical concerns. 1

Understanding the Result

A TSH level of 0.92 mIU/L falls within the normal reference range (typically 0.4-4.0 mIU/L), indicating euthyroid status. According to the American Thyroid Association guidelines, TSH is the primary screening test for thyroid dysfunction 1:

• Elevated TSH indicates hypothyroidism
• Suppressed TSH (<0.4 mIU/L) indicates potential hyperthyroidism
• Normal TSH (0.4-4.0 mIU/L) generally indicates normal thyroid function

Assessment Algorithm

1. Verify TSH is truly normal

   • Confirm the lab's reference range (typically 0.4-4.0 mIU/L)
   • TSH of 0.92 falls comfortably within this range

2. Determine if Free T4 testing is necessary

   • With TSH of 0.92, reflex Free T4 testing is not indicated 2
   • Research shows that restricting Free T4 measurement to individuals with TSH <0.3 or >5.0 mU/L is appropriate and reduces unnecessary testing 2

3. Consider clinical context

   • In asymptomatic patients with normal TSH, no further thyroid testing is needed
   • If patient has symptoms suggestive of thyroid dysfunction despite normal TSH, consider measuring Free T4

Clinical Implications

• A TSH of 0.92 does not indicate subclinical or overt hyperthyroidism, which would require a TSH <0.4 mIU/L 1, 3
• This value does not suggest hypothyroidism, which would present with elevated TSH 1
• No medication adjustment is needed for patients on levothyroxine with this TSH value 1

Common Pitfalls to Avoid

1. Overinterpreting minor TSH variations within the normal range

   • A TSH of 0.92 is not "borderline low" - it's solidly within normal range
   • Avoid unnecessary Free T4 testing when TSH is normal 2

2. Attributing non-specific symptoms to thyroid dysfunction when TSH is normal

   • Research shows that with TSH in the normal range, thyroid dysfunction is unlikely to be the cause of vague symptoms 1, 4

3. Failing to consider medications that might affect TSH

   • If the patient is on medications that can affect thyroid function, interpret results accordingly 1
   • Common medications affecting TSH include glucocorticoids, dopamine agonists, and some antiepileptics

Follow-up Recommendations

• No immediate follow-up thyroid testing is needed with a normal TSH of 0.92
• Routine thyroid screening can follow standard guidelines for the patient's age and risk factors
• If clinical suspicion for thyroid disease remains high despite normal TSH, consider measuring Free T4 and anti-thyroid antibodies

In conclusion, a TSH level of 0.92 is normal and does not warrant further thyroid function testing in the absence of compelling clinical symptoms or specific risk factors for thyroid disease.