Participants with an abnormal test result were randomized to @ of @ message formats designed to evaluate trade-offs between clarity and privacy : ( @ ) an SMS text message that stated results were abnormal and requested return to clinic ( `` direct '' ) , ( @ ) the same message protected by a @-digit PIN code ( `` PIN '' ) , and ( @ ) the message `` ABCDEFG '' explained at enrollment to indicate abnormal results ( `` coded '' ) .