Prevalence of Treponema pallidum DNA among blood donors with two different serologic tests profiles for syphilis in São Paulo, Brazil.

The presence of Treponema pallidum DNA was assessed by real-time PCR in samples of blood donors with reactive serologic tests for syphilis. Treponema pallidum DNA was detected in two (1·02%) of 197 samples of VDRL>8, EIA+ and FTA-ABS+ donors, and in no sample from 80 VDRL−, EIA+ and FTA-ABS+ donors. Donors VDRL−, EIA+ and FTA-ABS+ lack demonstrable T. pallidum DNA in their blood and are unlike to transmit syphilis. Donors VDRL>8, EIA+ and FTA-ABS+ carry the risk of syphilis infectivity even in concomitance to antibodies detection. Serologic screening for syphilis may still play a role to prevent its transfusion transmission.