Objective: To propose an improved method for constructing the internal quality control (IQC) framework for ELISA assays and validate its efficacy by statistically analyzing IQC data from nine blood center laboratories. Methods: 1) IQC data was collected from nine blood centers and analyzed using a domestic HBsAg ELISA detection kit as an example. 2) Differences between IQC values across batches within Blood Center 1 were assessed. 3) Statistical analyses were performed on batch usage, number of batches used, days of use, number of QC points, batch-specific means, and coefficients of variation (CV) across all nine centers. 4) Using the improved construction method for IQC framework, provisional and permanent frames were established for batches within Blood Center 1 and Blood Center 9, followed by outlier determination. Results: 1) Statistically significant differences were observed in IQC data between batches within Blood Center 1 (P<0.01). It is recommended that both the control material/reagents and the control chart framework be replaced simultaneously. 2) There were substantial differences among 9 blood centers regarding the control material/reagent lot numbers used, the number of QC runs per batch, and the QC values for identical lots. Therefore, individual laboratories should establish their own IQC chart frameworks. 3) The improved IQC framework construction method for ELISA assays is as follows: provisional frames are established via frame-shifting, using the pre-experimental mean and cumulative coefficient of variation (CV) from the preceding batch. For batches used >20 days with >20 QC points, permanent frames are constructed by aggregating in-control data accumulated over ≥20 days with ≥20 points to calculate cumulative mean and standard deviation. The provisional and permanent frames constructed by this method identified all 26 extreme outliers across Blood Centers 1 and 9 as out-of-control. Among the 218 general outliers, 10 were classified as normal by the provisional frames, while the remainder were designated as warnings or out-of-control. This method effectively monitors assay stability. Conclusion: Based on the statistical analysis of IQC practices across blood centers of varying scales, combined with the inherent characteristics of ELISA assays and the batch-to-batch instability of reagents/QC materials, it is recommended to reconstruct QC charts upon lot changes. The proposed method—utilizing frame-shifting for provisional frames and establishing permanent frames based on cumulative data—is applicable to blood center laboratories of differing sizes and effectively monitors the stability of the ELISA assay process.

Objective:To investigate the unqualified hepatitis C virus (HCV) detection result of blood donors from the served area of blood institutions.Methods:The data related to HCV markers detected of the first and repeat blood donors were collected from the system of practice comparison for the Chinese mainland blood institutions from 2017 to 2021. The anti-HCV reactive rate and the rates of anti-HCV negative but HCV-RNA reaction and all the relationship between rates and the annual, regional and different blood donors were statistically analyzed.Results:During 2017-2021, the number of anti-HCV reactive per 100 000 blood donors decreased from 444.3 to 250.44 in the served area of 22 blood institutions ( χ2=49.677, P<0.05). The number of HCV RNA detected positive per 100 000 anti-HCV negative increased from 0.69 to 2.05 year by year, but there was no statistical significance ( χ2=0.643, P>0.05). The anti-HCV unqualified rate was significantly different among regions ( χ2=3 260.283, P<0.05). The anti-HCV unqualified rate of the first blood donors was significantly higher than that of the repeated blood donors ( F=130.993, P < 0.05). The annual number of HCV RNA detected positive per 100 000 anti-HCV negative blood samples from donors ranged from 0 to 17.28. Conclusions:The anti-HCV unqualified rate of blood donors in the served area of 22 blood institutions decreased year by year. Compared with repeated blood donors, HCV infection should be emphasized in first-time blood donors. The implementation of HCV RNA test can detect out much more HCV infections and reduce the risk of transfusion transmitted infectious HCV.