“…The diagnosis is usually decided from reaction to administration of parathyroid hormone. The classical Ellsworth-Howard test (8) is often inconclusive, however (2,20). In our case this test showed that the patient reacted to PTH, but the increase in the phosphate excretion in the urine was of the same order of magnitude as in the healthy control ( (11,20), on the other hand, normalization of the serum calcium and serum phosphorus concentrations from clearly pathological values occurred, as in IHP (Fig.…”