Study on the confirmation of treponema pallidum antibody reactivity in blood donors / 中国输血杂志

ABSTRACT

【Objective】 To evaluate the feasibility of confirming syphilis reactive blood donors. 【Methods】 The serum of donors with anti-TP reaction by ELISA were confirmed by treponema pallidum particle agglutination (TPPA) and Western blotting (WB). The results of two confirmation methods that were negative, suspicious or inconsistent were followed up and compared. At the same time, the analytical index values of the screening reagent A, B and C and their combinations were evaluated and compared using the the receiver operating characteristic curve (ROC curve) based on the results of the two confirmation methods. 【Results】 The positive rate of 223 ELISA anti-TP reactive samples (including 124 double-reagent ELISA reactive samples and 99 single-reagent ELISA reactive samples) was 57.40% confirmed by TPPA and 38.57% confirmed by WB (89.52% vs 17.17% by TPPA and 52.42% vs 21.21% by WB for double-reagent and single-reagent ELISA reactive samples). The confirmed negative rate of TPPA was 35.43% and that of WB was 42.60% (6.45% vs 71.72% of TPPA and 29.84% vs 58.59% of WB for double-reagent and single-reagent ELISA reactive samples). According to Kappa test, the confirmed results between the two methods were not consistent, especially for those single-regent ELISA reactive samples. Thirty six cases were followed up successfully, of which 17 (47.22%) confirmed changes in the test results but the changes were irregular. Based on the confirmed results of TPPA and WB, the ROC curve analysis was performed on the anti-TP screening S/CO values of double-reagent ELISA reactive samples. When combining ELISA screening reagents as A/B and A/C, the optimal S/CO values of reagent A were 1.815, 5.73 and 10.205, 16.165, respectively. 【Conclusion】 TPPA and WB have poor consistency in the confirmation of ELISA anti-TP reactive blood samples, and the outcome of follow-up confirmation is unclear. The S/CO threshold of ROC curve is affected by the combination of confirmatory screening reagents, and it is difficult to confirm the results of ELISA anti-TP reactive blood donors.