Rhode Island DNA & Drug Testing: Find Clinic Locations by City Drug Testing and DNA Testing Locations in Rhode Island: Health Street has 13 Clinics in 10 RI Cities CranstonEast GreenwichJohnstonLincolnMiddletownNorth SmithfieldProvidence DNA TestingProvidence Drug TestingWakefieldWarwickWoonsocket DNA TestingWoonsocket Drug TestingMarijuana Laws in Rhode Island:THC is permitted, with a doctor’s prescription, for medical use only in the state of Rhode Island.