Table 1:

Laboratory parameters to identify the causes for imbalances in calcium homeostasis and osteoporosis (only selected conditions).

Parameter	Low	High
Calcium	Vitamin D deficiency, hypochlorhydria, hypoparathyroidism, renal insufficiency (renal loss), secondary hyperparathyroidism	Primary hyperparathyroidism, tumor (i.e. multiple myeloma), sarcoidosis
Phosphate	Vitamin D deficiency, hyperparathyroidism, renal insufficiency (renal loss)	Elevated intake, rhabdomyolysis, renal insufficiency
Alkaline phosphatase	Hypophosphatasia	Liver disease, Paget’s disease, osteomalacia
25-OH-D3	Insufficient intake or production in the skin	Vitamin D intoxication (very rare)
PTH	Hypoparathyroidism	Primary, secondary, or tertiary hyperparathyroidism
Osteocalcin/P1NP	Low turnover osteoporosis	Teriparatide
Deoxypyridinoline/β-CTX (urine)		High turnover osteoporosis, vitamin D insufficiency, hyperparathyroidism, hyperthyroidism

P1NP, Procollagen type 1 amino-terminal propeptide; β-CTX, β-crosslaps.