T4

Also called Thyroxine, Total T4

What it measures

Indian reports use µg/dL; nmol/L is the international form. As with T3, the total measures bound plus free hormone, which is why a free T4 is often ordered when the total is hard to interpret.

Reading it in a different unit

This lab reports T4 in ug/dl. Reports from other labs — especially ones using European or US-style formatting — sometimes use a different unit for the same measurement. The relationship between them:

Reported unitHow it relates to ug/dl
nmol/lug/dl = nmol/l × 0.077687

Unit conversions verified against published molar masses and LOINC definitions. This is not a diagnostic reference — the normal range for any test is set by the laboratory that ran it and printed on your report.

Why this matters for tracking a trend

A value plotted next to earlier results only tells you something if every point is on the same scale. Two readings of the same test from two different labs, in two different units, can look like a dramatic change when nothing about your actual result changed — only the unit did. Converting to one scale before comparing is what keeps a trend line honest.

LOINC code for this test: 3026-2.

General information about laboratory measurement, not medical advice. Whether a specific result is normal for you depends on your lab's reference range, your history and your doctor's judgement — not on this page.