St. Mary's County Health Department (SMCHD) Testing. Appointment-free PCR testing; ... Rapid PCR results are available online via the SMCHD patient portal. Care Recommendations. ... 21580 Peabody St. Leonardtown, MD 20650 Phone 301-475-4330 Fax 301-475-4350 TYY: 1-800-735-2258.