Which thyroid medication should patients avoid before a TFT draw?

Patients should avoid taking Armor thyroid before a Thyroid Function Test (TFT) draw because this medication contains both T4 (levothyroxine) and T3 (liothyronine) hormones, which can artificially elevate thyroid hormone levels in the blood. This elevation can lead to misleading test results, making it difficult for healthcare providers to accurately assess thyroid function.

Levothyroxine is a synthetic form of T4 and is also a common thyroid medication, but it is often considered less problematic for testing purposes compared to a combination treatment like Armor thyroid. Thyrolar, which contains both T4 and T3, may similarly affect TFT results but is not as frequently prescribed as Armor thyroid. Zoloft, an antidepressant, does not have a direct impact on thyroid hormones and is not relevant in this context since it does not alter the results of TFTs.