AMHERST MEDICAL CENTER. 31 Hall Drive Amherst, MA 01002 Phone (877) 431-2119 Fax 1-866-644-0871 Office Hours: Monday-Friday, 8am-6pm Saturday Urgent Care, 10am-1pm Full service laboratory on site. Hours are Monday-Friday, 6am-5pm Saturday, 7am-10:30am.