Serological diagnosis of Mediterranean spotted fever.

Complement fixation and indirect micro-immunofluorescence (IF) tests were compared for specificity and sensitivity in detection of antibodies against Rickettsia conorii, in acute and convalescent human sera. Purified particulate rickettsial antigens were used. Good agreement between these two tests was found. Use of specific anti-IgG and anti-IgM sera in parallel IF tests made it possible to differentiate between recent and past infections.