Reference ranges
TSH reference range
Reference ranges describe the interval a laboratory prints next to your result. They are not a diagnosis of what is “normal” for you personally — your clinician interprets results in context.
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What TSH measures
TSH helps regulate thyroid hormone production. Labs report a blood concentration; related thyroid hormones may appear on the same or separate reports.
Why ranges differ
Laboratories set their own reference intervals using their methods, equipment, and population data. That is why the range on your Quest report may differ from a LabCorp report — always use the interval printed on your source document.
Common units
TSH is often reported in mIU/L. Confirm units on your original report before comparing values across time.