The Mass General Back Bay Health Center Blood Draw Lab is open to Mass General Brigham patients with an open laboratory order from their Mass General Brigham provider. Laboratory appointments are required for blood draws. Please call to schedule an appointment or schedule through Patient Gateway. The blood draw lab is open Monday through Friday from 8:30 am to 4:30 pm. The lab is closed from 12:15 pm to 1:15 pm daily. Closed weekends and holidays.