Response to the Letter to the Editor by Dr. Rosario: “The calcium-to-phosphorous (Ca/P) ratio in the diagnosis of primary hyperparathyroidism and hypoparathyroidism: a multicentric study”

Excerpt

In reply to Dr Rosario, we would like to thank Dr Rosario for his interest in our article and the constructive comments [1]. Focusing on the diagnosis of normocalcemic primary hyperparathyroidism (NPHPT), the use of ionized Ca (iCa) is recommended in those patients with normal total calcium (Ca) and elevated parathyroid hormone, especially in the absence of an apparent cause of secondary hyperparathyroidism. Unfortunately, in our retrospective study [2] we did not report any data about iCa measurements since it was available only in few patients with NPHPT. For future research purposes, we agree with Dr Rosario that it would be interesting to analyze the sensitivity of calcium-to-phosphorus (Ca/P) ratio in NPHPT patients with normal iCa. Literature would have helped in exploring this issue. At present, biochemical characterization of NPHPT by using iCa is focused on the Ca × P product [3], which is an index so far studied only in nephropathic patients, but not on the Ca/P ratio. …