The diagnostic value of parathyroid hormone washout in primary hyperparathyroidism patients with negative or equivocal 99 m Tc-MIBI results.

FNA-PTH can be used to establish the nature of the lesion, discriminate parathyroid gland from thyroid lesions or cervical lymph nodes, improving the surgical outcomes. It can be used to localise parathyroid lesions preoperatively when negative or discordant ultrasound and scintigraphy findings are obtained.