Short Ammonium Chloride Loading Test for Evaluation of Hyperparathyroidism

Abstract

The dilemma in the diagnosis of hyperparathyroidism (HPT) is reflected by three factors: Hypercalcemia is still regarded as the most important diagnostic sign, but unless multiple determinations of serum calcium are done, the so-called borderline cases will be missed. Tests that readily identify HPT combine either simple performance, widespread use and low accuracy (C_P, TRP, PEI, T_MP/GFR)^l or sophisticated methods, limited use and high accuracy (PTH, Ca⁺⁺⁺, c-AMP). Consequently, some authors perform neck explorations to cure patients with recurrent nephrolithiasis who do not fulfill the diagnostic criteria of HPT. However, the stone recurrence rate may then reach 75%^2,3 In this situation, to complete the diagnostic puzzle of hyperparathyroidism additional information is valuable.