【Objective】 To compare the detection performance of Cobas s201, a minipool(MP) nucleic acid test(NAT) system, and Panther, a individual donation(ID) NAT system, in blood donor screening. 【Methods】 NAT was conducted on 126 359 blood samples, and initially reactive (IR) samples were either discriminated or resolved by ID testing.The non-discriminated reactive (NDR) samples implicated in Panther sysytem were subjected to ID-NAT by Cobas s201. Some non-repeatable reactivet(NRR) and repeatable reactive (RR) samples implicated in Cobas s201 system were subjected to ID-NAT by Panther. 【Results】 61 MP-IR cases were implicated in a total of 85 128 samples that detected by Cobas 201, and 29(0.34‰) were RR after resolved by ID testing. 74(1.79‰)IR samples were implicated in 41 231 samples that detected by Panther, and 22 (29.73%) were DR-HBV after discriminatory test. Among the NDR 28 samples detected by Panther multiplex system, 7 were positive by Cobas s201 single sample (PP1) whereas non-reactive in simulated MPs of six by Cobas 201.In 28 RR samples resolved by Cobas 201, 24 positive and 4 negative samples were retested by Panther. Among the 11 samples presenting inconsistent retest results by Panther and Cobas 201, 10 were anti-HBc positive, carrying low viral load HBV. 【Conclusion】 The NAT-yield by Panther was significantly higher than that by Cobas s201. Some samples with negative discriminatory results were OBI, and it is necessary to further track and verify the unidentified samples. Cobas s201 is more suitable for a wide array of MP-NAT testing while Panther sample loading, which is flexible and easy to operate, is more suitable for ID-NAT with medium sample size.

【Objective】 To study and analyze the serological and viral charactereristics of hepatitis B virus(HBV) infection in voluntary blood donors in Qingdao. 【Methods】 315 520 blood samples of voluntary blood donors were screened by ELISA combined with nucleic acid testing (NAT). All HBsAg-/HBV DNA+ samples were subjected to high-precision viral load detection and five serological markers of HBV. The sequence of HBV S gene was detected by PCR direct sequencing, and virus genotypes and amino acid mutations were analyzed. 【Results】 A total of 604(0.20%)HBV ELISA or NAT reactive samples were detected: HBsAg+ /HBV DNA- in 307(0.10%) cases, HBsAg-/HBV DNA+ in 138(0.04%) and HBsAg+ /HBV DNA+ in 157(0.05%). Among the 138 HBsAg-/HBV DNA+ donors, 118(85.5%) carried anti-HBc, and 45 (32.61%) carried sole anti-HBc and 5 (3.62%) carried both HBsAg and anti-HBc. In viral load detection, 64 were quantitatively negative and 74 were quantitatively positive, of which 42 were HBV DNA <20 IU/mL and 32 > 20 IU/mL. 13 HBsAg-/HBV DNA+ samples were successfully amplified and sequenced, and 5 were genotype B, presenting a total of 17 amino acid mutations without any deletion or insertion, and 8 were genotype C, presenting a total of 41 amino acid mutations and 2 amino acid deletions. 【Conclusion】 NAT, in combination of ELISA, provides additional safety in detecting potentially infectious HBV during the window period and occult HBV infection (OBI). The viral load was low in OBI infected donors, and anti-HBc+ was the main manifestation.The dominating HBV genotypes are genotype B and C, suggesting HBsAg amino acid mutations may be related to the formation of OBI.

【Objective】 To analyze the correlation between the distribution interval of minipool nucleic acid testing(NAT) positive CT value and the resolution rate, so as to improve the retest model and reduce residual risk of blood transfusion. 【Methods】 The resolution testing results by Cobas S201 system of our blood center from January 2017 to December 2021 were retrospective analyzed, and the retest model was developed based on the distribution interval of CT values. For minipool NAT HBV positive samples from March 2022 to March 2023, synchronous detection was conducted by Cobas S201 and Panther detection system, and the detection results were statistically analyzed. 【Results】 From 2017 to 2021, 474 were minipool NAT positive, among which 324 were HBV positive, accounting for 68.35%. From 2017 to 2020, the proportion of HBV positive per year was significantly higher than that of HCV and HIV(P<0.05). In resolution testing, 167 were HBV repeatable positive and 157 were HBV non-repeatable positive, accounting for 51.54% and 48.46% of HBV minipool NAT positive. HBV repeatable positive samples were with three intervals: CT value≤36, 3640, with the resolution rate at 95.8%, 56.5% and 14.8% respectively(P<0.05). The proportion of 3640, 36