[The relationship between parathormone and calcium blood levels in primary hyperparathyroidism. Diagnostic value (authors transl)].

The results of radio-immunoassay of parathormone in peripheral venous blood (using an anti-serum preferentially recognising fragments from the carboxyl-terminal pole) were compared with those of blood calcium measured on the same day in 33 cases of primary hyperparathyroidism. In the 28 patients with hypercalcaemia, PTH was invariably high (27 cases) or at the upper limit of normal (1 case). In the 5 patients with normal blood calcium levels, it was normal in 3 cases. It is thus important to take blood calcium levels into account in the interpretation of PTH estimation, that latter being more valid during a hypercalcaemic phase.