Can they determine if a nodule is hot or cold by just going by blood work results? such as tsh t3 (liothyronine) & t4 levels? my t3 (liothyronine) is high at 4.3 tsh and t4 are ok

Need more work up: I'm assuming you have a nodule. "Hot" or "cold" is determined by a radioactive iodine scan. A "hot" nodule may produce too much T3 (liothyronine) and/or T4, but if it did, the TSH should be low, and you say yours is normal. A "cold" nodule is more likely to be a cancer, and thyroid cancer usually does not affect the thyroid blood tests. You may need an Endocrinology consult, and a biopsy of that nodule.