Thyroid grade 4a nodule <5mm is a puncture is generally not recommended. Ultrasound-guided fine-needle aspiration refers to ultrasound-guided puncture of the thyroid gland with a fine needle to obtain cellular components for diagnosis of the nature of the lesion. The indications include: thyroid nodules >1cm in diameter with signs of malignancy on ultrasound; thyroid nodules <1cm in diameter, but combined with one of the following: ultrasound suggestive of malignancy in the thyroid gland; accompanied by ultrasonographic abnormalities in the cervical lymph nodes; a family history of thyroid cancer or a history of thyroid cancer; a history of radiation exposure to the neck or exposure to radioactive contaminants in childhood, and so on. The smaller the thyroid nodule lesion, the more difficult it is to puncture. If you find a grade 4a thyroid nodule, you need to consult a regular hospital and follow your doctor's instructions.