Thyroid Function Interpreter
TSH · Free T4 & Free T3 · ATA / ETA 2022 Guidelines · Pregnancy-specific ranges
TSH — the primary thyroid marker
mIU/L (same as μIU/mL)
Free T4 and Free T3 (optional but recommended)
ng/dL · Normal: 0.8 – 1.8 ng/dL
pg/mL · Normal: 2.3 – 4.2 pg/mL
Thyroid antibodies (optional — for autoimmune screening)
IU/mL · Normal: < 35 IU/mL
IU/mL · Normal: < 40 IU/mL
Patient context
Male
Female
Treatment context
ⓘ TSH has a log-normal distribution and should always be interpreted in context — age, sex, pregnancy, medications and symptoms all affect interpretation. A single TSH value alone is never sufficient to diagnose thyroid disease; always correlate with Free T4 and clinical presentation.
Please enter a valid TSH value (0.001 to 100 mIU/L).
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mIU/L TSH
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TSH spectrum — your position
Overt hyper <0.1
Sub hyper 0.1–0.4
Normal 0.4–4.0
High normal 4–10
Sub hypo 4–10
Overt hypo >10
TSH
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Free T4
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Free T3
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Reference range
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Typical symptoms at this TSH level
Treatment & monitoring guidance
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Clinical flags
ⓘ For clinical decision support only. Not a substitute for physician judgment.
TSH interpretation based on ATA 2014 Hypothyroidism Guidelines, ATA 2016 Hyperthyroidism Guidelines,
and ATA 2017 Thyroid Disease in Pregnancy Guidelines.
Pregnancy-specific TSH targets per Lazarus J et al., European Thyroid Journal 2014.
Free T4 and Free T3 reference ranges are method-dependent — always compare against the
laboratory-specific reference range. TSH alone is insufficient to diagnose thyroid disease.