Development of blood transfusion external quality assessment program at national scale

Introduction: External quality assessment is a crucial component in ensuring the quality of blood transfusion testing laboratories. Objectives: To develop a procedure for generating external quality assessment items for blood transfusion testing to evaluate participants' performance. Methods: Experimental research was conducted at Quality Control Center for Medical laboratory- University of Medicine and Pharmacy at Ho Chi Minh City, Vietnam. Three items, including red blood cell, serum, and atypical antibody serum samples, were assessed for homogeneity and stability; 5 assessment areas, including ABO grouping, Rh grouping, compatible cross matches, Coombs test, and screening of atypical antibodies, were utilized to evaluate the performance of 38 participants in the 2020-2021 period. Results: Red blood cell and serum samples maintained quality for a specific period at controlled temperatures, while serum samples with atypical antibodies showed stability at different temperatures. The participants demonstrated high satisfactory performance in ABO grouping, Rh grouping, Coombs test, and screening for atypical antibodies. However, the most unsatisfactory performance was reported in crossmatching, with 15% of participants unsatisfactory results. Conclusion: The procedure of production of proficiency testing items has been successfully developed, and its application at the national level is suggested to improve the quality of blood transfusion laboratories

Establishment of an Experimental Procedure for Preparing Trial Serum Samples for the Specific Serodiagnosis of Toxocara canis for External Quality Assessment Schemes

Background. External quality assessment (EQA) provides evidence of reliable, accurate, and precise results for customers using the diagnostic test for Toxocara canis. Objective. To establish a procedure for producing standard Toxocara canis serum samples for serodiagnostic testing in EQA. Methods. The collected serum samples to contain anti-Toxocara canis antibodies were screened by ELISA and confirmed by Western blotting. These samples were found to be negative for other helminth antibodies, anti-HIV-1 and -2 antibodies, anti-HCV antibodies, and antibodies to HBs antigen. The sera were divided, processed by both freeze-drying and freezing methods, and then stored. The stability and homogeneity of the samples were evaluated after 7 days, 1 month, 3 months, and 6 months. An F-test and a T-test were applied to evaluate their homogeneity and stability. Results. Among eleven samples positive by ELISA, ten of them were confirmed via Western blotting by positive reaction with 5 specific Toxocara canis bands. Two lots of trial standard sera containing specific anti-Toxocara canis antibodies were successfully produced. Lot DK had a concentration of 31.01±1.1 NovaTec Units (NTU), and Lot DL had a concentration of 27.18±0.9 NTU. After storage at -80°C, the samples prepared by the freeze-drying method were stable for at least 3 months, and the samples prepared by the freezing method were stable for 6 months (p>0.05). Samples produced by both methods were stable for 7 days at 30°C (p>0.05). Conclusion. Specific serodiagnosis samples of anti-Toxocara canis antibodies for EQA could be produced that possessed homogeneity and stability lasting for 3 months and 6 months by the freeze-drying and freezing methods, respectively. At 30°C, the samples produced by both methods were stable for 7 days, suitable for delivery to remote laboratories

Determination of Caffeine, Chlorogenic Acid, Total Phenolic Contents, and Antioxidant Capacities for Arabica and Robusta Coffee from Vietnam

In Vietnam, the cultivation and production of coffee have been expanding over the past few decades and are known as an important part of the national economy. However, the scientific data regarding the internal compositions of coffee have still been limited, especially the changes during the processing, typically the roasting period. The present study aimed to demonstrate an insight into the variations in chlorogenic acid, caffeine, total phenolic contents (TPCs), and trolox equivalent antioxidant capacities for two common coffee species, that is, Robusta and Arabica, and three roasting levels, that is, light, medium, and dark. Generally, Robusta coffee performed higher chlorogenic acid, caffeine, and TPCs, resulting in dominant antioxidant capacities compared to Arabica. High Pearson correlation coefficients (calculated by SPSS) were found for most pairs of parameters, r > 0.80. Regarding roasting levels, a descending order was highlighted for most analytical parameters: light > medium > dark. Two parallel processes in the roasting period were revealed by observing the antioxidant capacities, that is, thermal degradation and formation of other antioxidants by the Maillard reaction. Principal component analysis (SIMCA-P 11) was attempted to discriminate the available coffee samples by their species and roasting levels, indicating proper classification (the cumulative variance is 95.3%).</p