Application value of nucleic acid testing in syphilis screening reactive blood / 中国输血杂志

ABSTRACT

【Objective】 To evaluate the application value of nucleic acid testing (NAT) by studying the NAT-yield of syphilis screening reactive blood from five blood centers. 【Methods】 The blood samples and demographic information of syphilis screening positive donors were collected from five domestic blood centers, i. e. Chongqing, Guangxi, Luoyang, Liuzhou, Mianyang and Urumqi. The treponema pallidum particle agglutination (TPPA) and the established SYBR Green qPCR method were used to analyze the difference between the results of NAT and the other two test results. 【Results】 Among 1 679 reactive blood samples for syphilis screening, 819 were confirmed positive by TPPA, accounting for 49%, with the false positive rate exceeded 50%. As to NAT results, the NAT-yield of syphilis screening reactive samples and confirmed positive samples was the same (both 2.20%); the NAT-yield of TPPA-positive and TPPA-negative samples were 2.20% and 2.74%, respectively. 【Conclusion】 Primary syphilis screening by ELISA has high sensitivity, but also presents high false positive rate. Although TPPA confirmatory test has strong specificity, it cannot reflect the existence of T. pallidum. Therefore, NAT may be used as a supplementary test for syphilis screening so as to more effectively ensure the safety of blood transfusion and blood supply.