Urine calcium and serum ionized calcium, total calcium and parathyroid hormone concentrations in the diagnosis of primary hyperparathyroidism and familial benign hypercalcaemia.
A relationship between serum concentrations of ionized calcium and parathyroid hormone (PTH) in persons without parathyroid overactivity was defined by performing an oral calcium load test. As a result, a serum PTH concentration greater than 2.6 pmol/L in a hypercalcaemic patient was regarded as suggestive of hyperparathyroidism. Fasting serum PTH concentrations in 58 patients with surgically and histologically proven primary hyperparathyroidism (PHPT) were all above 2.7 pmol/L (range 3.2-84.5). Thirteen of 20 patients with familial benign hypercalcaemia (FBH) had fasting serum PTH concentrations greater than 2.6 pmol/L (range 1.6-6.1). There was a significant correlation between serum PTH and age in the FBH patients only. Fasting urine calcium excretion (CaE) ranged from 14 to 222 mumol/L of glomerular filtrate in PHPT and 3-34 mumol/L of glomerular filtrate in FBH. The best biochemical discriminant between patients with PHPT and FBH was a plot of fasting serum PTH against CaE. A plot of post-calcium load PTH against post-load CaE showed no further significant advantage in discriminating between the two conditions.
Gunn
I R
IR
Department of Biochemistry, Law Hospital, Carluke, UK.
Wallace
J R
JR
D000293:Adolescent; D000328:Adult; D000368:Aged; D002118:Calcium / Q000097:blood* / Q000652:urine; D002648:Child; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood / Q000175:diagnosis* / Q000652:urine; D006961:Hyperparathyroidism / Q000097:blood / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*
D010281:Parathyroid Hormone; D002118:Calcium