Can isoechoic thyroid nodule of 7mm be diagnosed by fnac test?

Yes: Yes image guided fine needle aspiration cytology will give diagnosis , a low risk out patient procedure.

Difficult: Thyroid nodules are very common. Under 1 cm, they are usually observed, meaning a repeat Ultrasound in one year. A FNA is difficult to actually target and sample such a small lesion. Okay to ask about medication and observation. Take a friend with you to appointment. If FNA is done, ask for confirmation at the test, that the lesion was sampled. Be well.