Assessment of Your Thyroid Function Tests
Your thyroid function tests are completely normal and do not require any treatment. 1
Understanding Your Results
Your laboratory values fall well within the standard reference ranges for thyroid function:
- TSH 1.81 mIU/L – This is solidly within the normal reference range of 0.45-4.5 mIU/L and close to the geometric mean of 1.4 mIU/L seen in disease-free populations 1, 2
- Total T3 1.09 nmol/L – Within normal limits 3
- Free T4 0.85 ng/dL – Within the normal reference range 1
The combination of normal TSH with normal free T4 definitively excludes both overt and subclinical thyroid dysfunction. 1 TSH has a sensitivity above 98% and specificity greater than 92% for detecting thyroid problems, making it an extremely reliable screening test 1, 4
Why No Treatment Is Needed
TSH Below the Treatment Threshold
- Guidelines recommend against routine treatment when TSH is between 0.45-4.5 mIU/L with normal thyroid hormones 5
- Treatment is only considered when TSH persistently exceeds 10 mIU/L or when TSH is elevated with low free T4 1
- Your TSH of 1.81 is far below any threshold that would warrant intervention 1
No Evidence of Subclinical Disease
- Subclinical hypothyroidism requires TSH >4.5 mIU/L with normal free T4 – you do not meet this definition 1
- Subclinical hyperthyroidism requires TSH <0.1-0.45 mIU/L with normal free T4 – you do not meet this definition either 6
- Your results indicate normal thyroid function without any subclinical abnormality 1
When to Recheck Thyroid Function
Asymptomatic individuals with normal thyroid function tests do not require routine screening intervals. 1 You should have thyroid function rechecked only if:
- You develop symptoms of hypothyroidism (unexplained fatigue, weight gain, cold intolerance, constipation, dry skin) 1
- You develop symptoms of hyperthyroidism (palpitations, weight loss, heat intolerance, tremor, anxiety) 1
- New risk factors emerge (starting certain medications like amiodarone or lithium, pregnancy, family history of thyroid disease) 1
Important Caveats
Normal TSH Variability
- TSH values can naturally vary by up to 40-50% due to pulsatile secretion, time of day, and physiological factors 1, 3
- A progressive increase in TSH over time while remaining within normal limits does not indicate thyroid disease 1
- Individual variation within a person is much smaller than variation between different people 3
Factors That Can Transiently Affect TSH
TSH values can be temporarily altered by:
- Acute illness or hospitalization 1
- Recent iodine exposure (such as CT contrast) 1
- Certain medications (dopamine, glucocorticoids, lithium) 1
- Recovery phase from thyroiditis 1
None of these factors change the interpretation of your normal results, but they are worth knowing for future reference.
Critical Pitfall to Avoid
Do not initiate treatment or pursue further thyroid workup based on normal TSH values, even if you have non-specific symptoms like fatigue. 1 Symptoms of thyroid dysfunction are extremely non-specific and prevalent in the general population, and treating normal thyroid function tests does not improve these symptoms 5, 4. Approximately 30-60% of mildly abnormal TSH values normalize spontaneously, highlighting the importance of not triggering unnecessary interventions 1
Your thyroid is functioning normally and requires no intervention at this time. 1