Pre- and postoperative evaluation of renal function with five different tests in patients with primary hyperparathyroidism

Renal function was investigated immediately before and 1 year following parathyroidectomy in 19 patients with moderate hypercalcaemia. On both occasions, all patients underwent five different tests of glomerular and tubular function: plasma creatinine, creatinine clearance, 51Cr-EDTA-clearance, beta 2-microglobulin excretion and the desmopressin test. Glomerular filtration rate, as assessed by plasma creatinine and clearance of both creatinine and 51Cr-EDTA, was normal in most patients, and was little affected by restoration of normocalcaemia. Renal concentrating capacity, as determined by the desmopressin test, was abnormally low in 14 of 19 patients, but increased significantly after surgery. It is concluded that serious renal damage is seldom encountered in present-day HPT patients, but that a treatable decrease in renal concentrating capacity often exists.