Feeling cold when others are comfortable — cold hands and feet, or never feeling warm in winter — is a classic sign of an underactive thyroid or iron deficiency. Here are the tests that tell them apart.
Cold intolerance points clearly toward thyroid and iron — but the tests that confirm them are often the ones left off a routine panel.
Cold intolerance is one of the more specific symptoms in this group: it points strongly toward two causes, both common and both treatable. The thyroid regulates how much heat your body produces, and iron is needed to carry oxygen and maintain circulation to your extremities.
The catch is that the confirming tests are routinely skipped. A standard thyroid check is often TSH alone, which can miss a sluggish thyroid where the active hormones (free T4 and free T3) tell the fuller story. And a CBC detects anaemia only once haemoglobin drops — ferritin, which shows iron depletion months earlier, is rarely included unless you ask.
The two clusters below are what a cold-intolerance workup actually needs. If you also have fatigue, dry skin, or hair thinning alongside the cold, that combination strengthens the case for checking thyroid and iron together.
The two causes most associated with feeling cold all the time — checked properly, not just at the surface.
Doctors order what they're used to ordering. Being specific about what you want, and why, changes the conversation.
Getting the right tests ordered is step one. Reading the results properly is step two.
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