Abstract: Objective Syphilis confirmatory testing and syphilis infection status analysis of the blood donors on the unqualified results of anti-TP antibody screening, in order to provide the reference of setting the scientific and reasonable grey area and informing the test results of the blood donors and shielding the blood donors. Methods From 24 March to 2 October in 2016, 290 blood samples of the blood donors on the unqualified results of screening anti-TP antibody were collected in Anhui blood center. Syphilis confirmation was performed by TPPA and the agglutination titer of the Non-treponema pallidum antibody was detected by TRUST. Results 290 unqualified samples of anti-TP antibody screening were confirmed by TPPA, there were 166 TPPA positive samples and 124 TPPA negative samples. There were 50 TRUST positive samples among 166 TPPA positive samples. The positive rate of anti-TP ELISA screening reagent 1 and reagen 2 showed no significant difference （P>0.05）. There wasn't TPPA positive samples among 107 samples with single reagent positive and double reagent grey area for anti-TP antibody ELISA screening. Among 290 unqualified samples of anti-TP antibody screening, there was no significant difference （P>0.05） between male TPPA positive rate （57.31%） and female TPPA positive rate （57.14%）, there was significant difference that the married persons TPPA positive rate （68.78%） was higher than the unmarried persons its （35.64%） （P<0.05）, the married males TPPA positive rate （70.18%） was higher significantly than the unmarried males （31.58%） （P<0.05）, the married females TPPA positive rate （66.67%） was higher significantly than the unmarried females TPPA positive rate （40.91%） （P<0.01）, the TPPA positive rate of the once blood donors （61.07%） was higher significantly than its of 2 times and above 2 times blood donors （27.27%） （P<0.05）, the TPPA positive rate of the different education background persons had significant difference （P<0.05）, the TPPA positive rate of the different ABO blood group persons had no significant difference （P>0.05）. Conclusion The anti-TP antibody ELISA screening test exists a certain proportion of false positive. In order to avoid the leakage of weak positive specimens, the blood screening laboratory should monitor the performance of the test, set the scientific and reasonable grey area, and reduce the unnecessary blood waste. In order to inform of the blood donors and reduce loss of the blood donors, and establish a stable and sustained team of the blood donors,it was recommended that syphilis confirmation testing of the blood donors on the unqualified results of anti-TP antibody screening was added in the blood station. The results information feedback of the blood donors should refer to the syphilis confirmation results. The syphilis confirmation result should be referenced as the basis for shielding the unqualified blood donors. The syphilis infection rate is higher among the blood donors on the unqualified results of anti-TP antibody screening, especially married persons and low education background persons. When the test results feedback of the blood donors of the TPPA positive and TRUST titer positive, it was recommended that they were tested in clinical medical institutions as soon as possible, so that reinfection syphilis, latent syphilis （recessive syphilis） persons could be treated in time and avoided disease transmission.

Key words: Blood donors, Treponema pallidum, Antibody titer, Confirmatory tests, Blood donors shielding