PTH and hypoparathyroidism: Statement 16: Long-term follow-up data necessary for assessing prevalence of permanent hypoparathyroidism should include serum calcium (albumin-adjusted and/or ionized) and PTH levels at 12 months after surgery, and information if an attempt was undertaken at stopping supplements within 12 months after surgery with failure to stay off supplements due to low calcium and/or reoccurring symptoms.