ABSTRACT
【Objective】 To evaluate the infection status and potential infectivity of Treponema pallidum specific antibody (anti-TP) reactive blood donors, and to provide reference for the key prevention and screening of TP under the current screening strategy. 【Methods】 From February to October 2021, 133 blood donors were tested reactive by two different anti-TP ELISA kits (77 cases were dual-reagent reactive and 56 cases were single-reagent reactive). Syphilis specific IgM antibody (TP-IgM) and IgG antibody (TP-IgG) were detected by Western blot (WB), and TRUST was conducted. The results were analyzed. 【Results】 Of the 133 samples, 24 (18.05%) were positive for TP-IgM, 40 (30.07%) were positive for TP-IgG, and 3 (2.26%) were positive for TRUST. Among them, 12 cases (15.58%) were TP-IgM positive and 40 cases (51.95%) were TP-IgG positive in 77 cases of double reagent reactivity, and 12 cases (21.43%) were TP-IgM positive and 0 was TP-IgG positive in 56 cases of single reagent reactivity. There was no significant difference in the positive rate of TP-IgM between the two groups (P>0.05), while the positive rate of TP-IgG in donors with double reagent reaction was higher than that in donors with single reagent reaction (P<0.05). In addition, among the 133 anti-TP-reactive blood donors, 15 cases were positive for single TP-IgM (11.28%, accounting for 62.50% of the total positive number of TP-IgM, a total of 12 cases of TP-IgM positive among the single reagent reactive patients, and all of them were TP-IgM positive and TP-IgG negative); 30 cases were positive for single TP-IgG (22.56%, accounting for 75.00% of the total positive number of TP-IgG). There were 55 cases (41.35%) who were negative for TP-IgM and TP-IgG, and 8 cases (6.02%) were both positive. 【Conclusion】 The TP-IgM positive donors in anti-TP reactive blood donors are infectious, but the positive rate is not high. Those with single reagent reactivity and single TP-IgM positive are prone to miss detection, which should be controlled. Those who were both TP-IgM and TP-IgG negative and those who were only TP-IgG positive may be false reactivity and the phenomenon of lifelong antibody expression. It is suggested to consider adding TP-IgM detection as a measurement index for permanent deferral of both reagents.
ABSTRACT
【Objective】 To verify the detection performance of a newly introduced individual donation(ID) nucleic acid detection(NAT) system, and to confirm whether its main test parameters meet the expected requirements of blood screening. 【Methods】 Standard serum and plasma negative for HBV DNA, HCV RNA, and HIV RNA were diluted to different multiples samples (0.5~3 times) of the detection system′s limit of detection (LoD). These samples were conducted NAT test for HBV DNA, HCV RNA and HIV-1 RNA, to verify the testing sensitivity, stability, accuracy and anti-interference ability. 【Results】 The sensitivity of 3× LoD concentration of HBV DNA, HCV RNA and HIV-1 RNA was tested by the system, and the yielding rates were all 100%, with 1 ×LoD at 95.0%~100% and 0.5×LoD at 70.0%~90.0%. The intra-assay and inter-assay precision variation coefficient was 2.07%~2.62% and 2.33%~2.88%, respectively. The accuracy of 10 external quality assessment samples of National Center for Clinical Laboratories was 100%. Severe hemolysis and fatty blood had no effect on the detection of samples with 3×LoD concentration of HBV DNA, HCV RNA and HIV-1 RNA. Any combinations by samples with 2 × LoD concentration of HBV DNA, HCV RNA, and HIV-1 RNA were not inhibited by high concentrations of other viruses. Among 2 041 sero-negative samples from blood donor, the NAT yield of this system was 1.67% (34/2 041), which was a little bit higher than that of a imported minipool system (1.66%, 33/2 041) (P>0.05). 【Conclusion】 The ID-NAT system can meet the requirements in terms of sensitivity, stability, accuracy and anti-interference ability, and can be used for blood screening of blood donors.