Total Calcium, and Albumin, or Ionised Calcium, Phosphate, Intact Parthyroid horrmone, Vitamin D, Alkaline phosphatase; fasting spot urine: Calcium and Creatinine
In primary hyperparathyroidism, a high serum calcium is found together with an increased or inappropriately high-normal PTH. Similar findings are seen in tertiary hyperparathyroidism, but following long term secondary hyperparathyroidism, usually as a consequence of chronic renal failure.
Secondary hyperparathyroidism is characterised by a raised PTH in association with a low or low-normal serum calcium, usually due to renal failure or vitamin D deficiency.
Reference: Eastel R et al J Clin Endocrinol Metab. 2014;99(10):3570-9
See also Multiple endocrine neoplasia