Retrospective analysis and grey zone verification of blood donors with anti-Treponema pallidum single reagent reactive results
10.13303/j.cjbt.issn.1004-549x.2026.02.009
- VernacularTitle:梅毒螺旋体抗体单试剂反应性献血者追溯性分析及灰区验证
- Author:
Qing HE
1
;
Feifei JIANG
1
;
Zhichao CHEN
1
;
Panpan WANG
1
;
Yousheng KONG
1
;
Suping LI
1
Author Information
1. Anhui Blood Center, Hefei 230031, China
- Publication Type:Journal Article
- Keywords:
blood donors;
Treponema pallidum;
single reagent reactive;
gray zone
- From:
Chinese Journal of Blood Transfusion
2026;39(2):224-228
- CountryChina
- Language:Chinese
-
Abstract:
Objective: To explore the setting of gray zone of Treponema pallidum (TP) testing by retrospective analysis of blood donors with single reagent reactive anti-TP results, so as to improve blood utilization and supply safety. Methods: Blood samples were collected from 112 blood donors previously deferred due to single reagent reactive TP antibody results between January 2020 and December 2023, and subjected to dual ELISA reagents and TPPA test. The gray zone panel analysis was performed on the two ELISA reagents currently used in our department. The detection rate at each concentration of the gray zone panle was counted, and the corresponding concentrations for C
, C
, and C
and gray zone cut-off were calculated. Results: Among the 50 samples deferred by reagent 1, 19 were confirmed reactive and 31 non-reactive in supplementary testing. Among the 62 samples deferred by reagent 2, 12 were confirmed reactive and 50 non-reactive in supplementary testing. For reagent 1, the detection rate of was 56% for S/CO≥1 and 20% for 0.5≤S/CO<1, retrospectively. For reagent 2, the detection rate was 27% for S/CO≥1 and 12.5% for 0.5≤S/CO<1, retrospectively. The detection rate for S/CO≥1 was higher than those for 0.5≤S/CO<1 for both reagents. All the 112 samples were negative in TPPA test. The C
concentration of reagent 1 was 1.51 mIU/mL, and the concentration range of C
±20% was 1.21-1.81 mIU/mL. The C
concentration of reagent 2 was 1.45 mIU/mL, and the concentration range of C
±20% was 1.16-1.74 mIU/mL. The C
and C
concentration of both reagents were within the C
±20% range, suggesting that the gray zone cutoff for both Reagent 1 and Reagent 2 should be set at S/CO=0.8 (80% of the CO value). Conclusion: All anti-TP single reagent reactive samples with S/CO value within the gray zone was tested negative by TPPA. It is necessary to consider the rationality and necessity of establishing the gray zone, so as to ensure blood safety and improve the utilization rate of blood resources.
