WhatDoMyLabResultsMean.com

Thyroid

Free T4

Also known as: Free Thyroxine, Thyroxine test by equilibrium dialysis

CPT 84144Quest 1759LabCorp 322000
Critical — Seek Care

If you experience sudden severe symptoms like a very fast or irregular heartbeat, severe anxiety, unexplained weight loss, or extreme fatigue, contact your clinician immediately or seek urgent care.

What It Measures

This test checks the amount of T4 in your blood. T4 is a hormone. This T4 is not stuck to other things. This "free" T4 is the part that works in your body. It helps your body's parts do their jobs right.

Why It's Ordered

Your doctor orders this test to see how your thyroid gland is working. This is especially true if you have signs of a thyroid that is too active or not active enough. The test also helps check if your thyroid medicine is working.

Reference Range

Reference ranges for Free T4 can vary between different laboratories and may also depend on factors like age, sex, pregnancy status, and clinical context. Always discuss your specific results with your healthcare provider.

Clinical Reference

Quest: 1759
LabCorp: 322000
CPT: 84144
ICD-10: N91.2, E28.319, O09.90

Medicare covers for hormonal evaluation

Educational purposes only — This information is not a substitute for professional medical advice, diagnosis, or treatment. Always discuss your lab results with your healthcare provider.