Low levels of total and ionized calcium in blood of COVID-19 patients

To the Editor, As of April 27, 2020, the SARS-CoV-2 pandemic caused worldwide more than 3 million cases with more than 200,000 confirmed deaths.Italy, following USA and followed by Spain, is the country with a higher number of deaths, more than 26,000, with most of them occurring in Lombardia region [1].Worldwide, hospital organizations have been deeply changed in the recent months; San Gerardo Hospital (Monza, Italy) increased its intensive care unit bed availability by almost 300% and a total of 20 wards were readdressed for the care of COVID-19 patients.Patients admitted to the emergency department (ED) with clinical signs and symptoms suggestive of COVID-19 have been investigated with nasopharyngeal swabs for SARS-CoV-2 (RT-qPCR) plus biochemistry, hematology and coagulation test panels.Overall, we found an increase in patients who had a reduction in serum total calcium (TCa, mmol/L) and whole blood actual ionized calcium (Ca 2+ , mmol/L) levels.Therefore, we retrospectively evaluated TCa and Ca 2+ in consecutive adult patients admitted to the ED during the period February 27th-March 30th and