The Indiana Blood Center says its blood supply levels across the Hoosier state are critically low.
The LGBT organization hosted the drive to honor the victims of the Orlando shooting, but had to send more than 100 people to other donation sites.
The FDA recommends people who travel to a country where Zika has been transmitted delay donating blood for at least 28 days after their return.
Three Indiana hospitals, including IU Health, switch blood suppliers from Indiana Blood Center to Red Cross.
The severe winter weather has depleted the Indiana Blood Center's supply of blood for hospitals.
Indiana Red Cross blood and platelet donations have dropped 13.5 percent since March and officials worry they will be facing a blood shortage later this summer.
The Indiana Blood Center suggests donors come in and give "double donations" to help maintain supplies.