The Wentworth-Douglass Hospital Blood Draw Lab - Professional Center at Lee is open to Mass General Brigham patients with an open laboratory order from their provider. No appointment is necessary, walk-in appointments are available. Walk-in appointments are welcome Monday through Friday from 7:00 am to 5:00 pm. 7:00 am to 5:00 pm. This lab is closed daily from 12:00 pm to 12:30 pm.