Our primary care clinic works with Patient Portal in order to ensure patients receive the best, most confidential service they can. Serving Elkridge, Columbia, Jessup & Ellicott City MD. ... COVID-19 Testing and FAQs now available for Centennial Medical patients. Open Today: 8:00 am – 4:30 pm . 8186 Lark Brown Rd Elkridge, MD 21075 (410) 730 ....