ROME — Italy’s health minister is appealing to citizens to answer the Red Cross call for a blood test to determine if they have antibodies to COVID-19.

Red Cross volunteers began making phone calls Tuesday to a representative sample of people throughout Italy. Minister Roberto Speranza told Sky TG24 TV the goal is to better understand how many people have developed antibodies.

Experts say many people without COVID-19 symptoms in the country where Europe’s outbreak began were likely infected but were never tested. Speranza says the blood test results of 150,000 people can be applied to the entire country.

Speranza says people with antibodies will quickly receive a test for COVID-19 to see if they have an active infection. Italy is considering a tentative lifting of restrictions of travel between regions in the country on June 3.

Scientists have cautioned they don’t know if antibodies guarantee immunity, and if they do, how long such immunity lasts.