Final answer:
Monitoring calcium levels is the priority action for a client post-operative following a parathyroidectomy.
Step-by-step explanation:
The nurse should identify monitoring calcium levels as the priority action for a client post-operative following a parathyroidectomy. This is because the parathyroid gland is responsible for regulating blood calcium levels, and after a parathyroidectomy, the client may experience imbalances in calcium levels. Monitoring calcium levels allows the nurse to identify any abnormalities and take appropriate actions to maintain the client's calcium balance.