【Objective】 To investigate the characteristics of NAT reactive(R) population among voluntary blood donors in Zhengzhou, and analyze the residual risk of NAT and the infection in different ages, educational levels, and occupations. 【Methods】 The samples of voluntary blood donors in Zhengzhou from 2018 to 2019 were comprehensively screened (samples reactive by duplicate ELISA reagents excluded), and the occupation, gender, education level and marital status of voluntary blood donors were analyzed. 【Results】 A total of 488 365 samples were detected, 323 were NAT R samples (0.66‰), including 318 HBV R samples (0.65‰) and 5 HIV R samples (0.01‰), but no HCV R was detected. Statistical analysis showed that NAT R rate in male voluntary blood donors was 0.78‰ (252/321 196), higher than 0.42‰ (71/167 439) in female (P<0.05); the NAT R rates of 18~25, 26~35, 36~45, 46~55, and over 55 years old group were, 0.21‰ (39/187 816), 0.56‰ (61/108 481), 1.03‰ (101/97 872), 1.27‰ (112/87 943), and 1.53‰ (10/6 523), respectively, showing an upward trend with age(P<0.05). The NAT R rate of donors of junior middle school education and below, high school education, secondary vocational education, college education, undergraduate education and above were 1.00‰(27/26 921), 0.99‰(62/62 375), 0.97‰(28/28 908), 0.37‰(43/117 643)and 0.43‰(55/126 992), respectively, showing a downward trend (P<0.05). Among different occupations, the NAT R rate of farmers was the highest as 1.10‰ (49/44 430), and those of medical personnel and students were rather low as 0.32‰ (4/12 666) and 0.21‰ (31/145 563), respectively (P<0.05). The NAT R rate in repeated blood donors was 0.75‰ (192/257 077), which was higher than 0.57‰ (131/231 558) in first-time blood donors (P<0.05), but no significant difference was noticed in blood group and ALT (P>0.05). 【Conclusion】 Some blood samples were negative by ELISA but reactive by NAT. Therefore, NAT is an effective supplement to missed detection of ELISA and can reduce the risk of transfusion transmitted infection diseases. The characteristics of NAT R population in Zhengzhou are worth studying, which can provide reference for health consultation and further improve blood safety.

【Objective】 To analyze the cause of single-ELISA reactive of four blood screening items in 18 blood stations in Henan, so as to provide the basis for improving the quality of blood screening. 【Methods】 The single-ELISA reactive rate of HBsAg, anti-HCV, HIV Ag/Ab and anti-TP of 18 blood station laboratories in Henan throughout 2019 was calculated, and the causes were analyzed according to different ELISA reagent combinations and gray area settings in each laboratory. 【Results】 The overall single-ELISA reactive rates of HBsAg, anti-HCV, HIV Ag/Ab and anti-TP were 1.740(2 154/1 237 789), 0.564‰(698/1 237 789), 1.421‰(1 759/1 237 789) and 1.561‰(1 932/1 237 789), respectively, showing significant differences by detection items (P <0.05). Person correlation analysis showed that the single-ELISA reactive rate was independent of the gray area settings.but dependent on laboratories and reagent combinations. The single-ELISA reactive rate of HBsAg, anti-HCV, HIV Ag/Ab and anti-TP in D laboratory was the highest and higher than that in other labs using the same reagent.The laboratories with high HBsAg single-ELISA reactive rate were mostly those using a combination of imported reagents and domestic reagents, including the top 6 laboratories. The laboratories with high anti-HCV single-ELISA reactive rate were mostly those using certain domestic reagents. No obvious rules was noticed by single-ELISA reactive for anti-HIV. Laboratories with high anti-TP single-ELISA reactive rate were mostly those using combination 4. 【Conclusion】 The HBsAg single-ELISA reactive rate was the highest in the four blood screening items of blood station laboratories in Henan. The single-ELISA reactive rate is related to the laboratory itself and the reagent manufacturer, suggesting that laboratory quality control should be strengthened and proper reagent combination should be selected to reduce the waste of blood.