[Value and relevance of metabolic function tests in the diagnosis of primary hyperparathyroidism (author's transl)]

Calcium, phosphate and alcaline phosphatase levels were determined in the serum of 29 patients with suspected primary hyperparathyroidism. Phosphate clearance according to Kyle, 24 hours urine hydroxyproline excretion during collagen free diet, the excretion of cAMP in the 24 h urine during calcium restricted diet were examined with regard to the diagnostic value and relevance as compared to the consumption of laboratory and staff time. The elevation of the serum calcium levels are not specific and only of minor diagnostic value. It has been found that the highest diagnostic value is given by the Kyle-test using 15 mg Ca ions/kg body weight. No false positive results were recorded. The excretion of hydroxyproline and calcium are only of limited value. Serum alcaline phosphatase and cAMP excretion have no diagnostic significance whereas concentration of serum phosphate may have some value.