Could a thyroid blood test miss a hypothyroid issue?

Thyroid testing: The tsh, free t4, and T3 (liothyronine) uptake will miss very little. Make sure that these are what you have had if you have had a blood test for hypothyroidism.

Yes: There are several parts to a thyroid blood test. Often only 1 part is used, called a TSH (thyroid stimulating hormone.) if it is high normal and a person has symptoms of low thyroid, like depression, weight gain, intolerance to cold, the practitioner often gets a different test, a free circulating thyroid hormone. When it's all borderline it is often worth a trial of low dose thyroid replacement.