@po1958ling The company that I use is Vital Tears phone number 800-360-9592. I am pretty sure they were based in Kansas City but are used by Mass Eye and Ear, Longwood Ave. Boston. It cost either $20.00 or $40.00 to have the nurse come to my house. I live in a suburb of Boston. They also gave me an address of a lab approxinately 25 minutes away but because I am 82 and don't love driving or falling on the ice so I opted to pay the extra and have the nurse come to my home. Sincerely, Diane Donohue