uIU/mL To mIU/L Converter

Direct Answer For TSH Reports

For thyroid-stimulating hormone, commonly shortened to TSH, 1 uIU/mL is numerically equal to 1 mIU/L. A result of 2.50 uIU/mL therefore converts to 2.50 mIU/L. This can look surprising because both the top and bottom parts of the unit change at the same time. Micro-international units are one thousand times smaller than milli-international units, while a millilitre is one thousand times smaller than a litre. The two changes cancel out, leaving the same number.

The converter is useful when a UK patient portal, private laboratory, overseas report or older letter uses a different label from another record. It is not a thyroid checker. TSH interpretation depends on the laboratory reference interval, symptoms, medicines, pregnancy status, pituitary context, thyroid history and clinician notes. Keep the source report with the converted unit rather than copying the number into a new record without context.

Formula And Unit Method

The conversion is a notation change, not a biochemical judgement. Use the same number of decimals as the report when possible. If a report states 2.47 uIU/mL, copy it as 2.47 mIU/L, not as 2.5 mIU/L, unless your own note clearly says the value has been rounded. Rounding before a medical review can make two close results look more different than they are.

uIU/mL To mIU/L Conversion Table

Related Thyroid Unit Notes

How To Copy The Converted Result

A clear record keeps both the original and converted form. For example: TSH 2.47 uIU/mL equals 2.47 mIU/L using a one-to-one unit conversion. That wording tells another reader that the second number is not a new test. It also protects the original unit, which may be important if the laboratory reference interval is printed beside the result. If you are sending a result to a GP, endocrinologist, fertility clinic or insurer, attach the original report where possible.

Do not use this page to decide whether a result is normal, high, low or urgent. Laboratories can use different methods and reference intervals. Pregnancy, thyroid medicine, acute illness, pituitary conditions and timing of medicine can all affect how a clinician reads the result. If the report has a warning, a flag or advice to speak to a clinician, follow that advice rather than relying on a converted unit label.

Comparing Two Thyroid Reports

If two reports use different unit labels, place them in a small record with date, laboratory, original unit, converted unit and reference interval. Do not delete the original unit after conversion. A clinician may need to see whether both results came from the same laboratory method and whether the reference range changed between tests. This is especially important when monitoring medicine changes, pregnancy-related checks or private tests copied into an NHS record.

Less-Than And Greater-Than Results

If the report shows a less-than or greater-than sign, keep the sign with the number when copying the conversion. The arithmetic is still one-to-one, but the sign tells the reader that the laboratory reported a limit or threshold rather than a plain measured value.