Table 1.

Expected biochemical changes with various causes of hypercalcemia

Disease	Total calcium	Ionized calcium	Phosphorus	PTH	PTHrP	PTG imaging
Primary hyperparathyroidism	↑	N or ↑	N or ↓	↑ or upper half of reference range	N or not detectable	↑ One gland typical
Hypercalcemia of malignancy	↑	↑	N or ↓	↓ or lower half of reference range	N or ↑, depends on tumor type	N or ↓
Chronic kidney disease	↓ , N, ↑	↓ , N, ↑	↑ or N	↑	N or not detectable	↑ Multiple glands
Idiopathic hypercalcemia	↑	↑	N	N or ↓	N or not detectable	N or ↓
Acute vitamin D toxicity	↑↑	↑↑	↑↑	↓	N or not detectable	N
Nutritional secondary hyperparathyroidism	N or ↓	N or ↓	N or ↓	↑	N or not detectable	N or ↑
Hypoadrenocorticism	↑	N or ↑	↑	N or ↓	N or not detectable	N