The research into and production of hematological reference samples used to implement an external quality assessment (EQA) to check the quality of hematology tests are necessary for hematology laboratories in Vietnam. In this research, the study team determined the assessment values of blood cell count (human RBCs, pseudo-leucocytes, and pseudo-platelets) by the impedance method used in hematology EQA programs. The hematological reference samples were controlled at three concentration levels: low, normal, and high. Determination of the assigned value (mean ± 2SD) was performed for the following hematology analyzer series by impedance method: ABX Micros 60, Celldyn 1700, and Mindray BC 2000. Each device was sent to 10 different laboratories for evaluation. Research results for assigned values of each model (ABX Micros 60, Celldyn 1700, and Mindray BC 2000) were determined at the three concentrations. For the ABX Micros 60 and Celldyn 1700 series, 80% of laboratories had analytical results within assigned values. For the Mindray BC 2000 series, 100% of laboratories had analytical results within assigned values. The measurement results for the number of human RBCs, pseudo-leucocytes, and pseudo-platelets on each analyzer were similar between the 10 laboratories; the results of the three hematology analyzer series using the impedance method were different and the difference was statistically significant (p < 0.05). Thus, hematological reference samples for measuring the number of blood cells meeting the standards so that they can evaluate the results of laboratories using the impedance method: ABX, Celldyn 1700, Mindray BC 2000.

The campaign “No action today, no cure tomorrow” against antimicrobial resistance proposed by the World Health Organization (WHO) has not only propeled people to take action to prevent antimicrobial resistance, but has also encouraged researchers to develop new antimicrobial agents. 4(3H)-quinazolinone and its derivatives belong to a group of compounds with many potential applications; this study was conducted to find new derivatives of heterocyclic 4(3H)-quinazolinone with biological effects, contributing to research on antibacterial and antifungal compounds. Using the closed-loop method between anthranilic acid and acetic anhydride, followed by reaction with aniline derivatives, a substituted product of position 3 of 4(3H)-quinazolinone was obtained, along with bromizing to replace the hydrogen of the methyl group in position 2 with dibromo. Heterocyclic derivatives such as imidazole, triazole, and thiazole were replaced from this dibromo product to obtain 19 derivatives. The structures of these derivatives were checked by modern methods such as IR, ¹H-NMR, and MS. The results indicated that all of the structures were as expected, so the process of creating new derivatives from 4(3H)-quinazolinone was achieved in this study. Fourteen of the derivatives, namely 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3m, 3o, 3p, 3q, 3r, and 3s, had antibacterial or antifungal effects. Among these, there were five potential derivatives: Antifungal activity was observed on A. niger by 3j and 3f (MIC: 32 μg/mL) and 3s (MIC: 64 μg/mL), and on C. albicans by 3f (MIC: 8 μg/mL); antibacterial activity was observed on S. aureus by 3p (MIC: 16 μg/mL) and 3f and 3r (MIC: 32 μg/mL), on MRSA by 3f and 3r (MIC: 32 μg/mL), and on E. coli by 3f (MIC: 32 μg/mL).

Hematological reference samples for external quality assessment (EQA) in hematology are essential for many laboratories in Vietnam, however, the prices are high along with short storing time. This study attempted to establish an optimal formula for the manufacture of hematological reference samples for hematological EQA programs. Human red blood cells (RBCs) were mixed with goose RBCs (pseudo-leucocytes) and goat RBCs (pseudo-platelets) as alternatives for white blood cells (WBCs) and platelets (PLTs), respectively, in different formulas of storage media. The optimal formula was obtained using response surface methodology–central composite design (RSM-CCD). Three main factors affecting the concentrations of RBCs were determined by Plackett–Burmann matrix. The optimal concentrations determined by RSM-CCD were 46% serum, 0.44 g/L neomycin sulfate, and 2.5% glycerol. The model predicted that the maximum number of human RBCs was 4.1 × 10¹² cells/L, pseudo-leucocytes was 6.4 × 10⁹ cells/L, and pseudo-platelets was 188 × 10⁹ cells/L. The practical concentrations of RBCs, pseudo-leucocytes, and pseudo-platelets were 4.21 × 10¹² cells/L, 6.4 × 10⁹ cells/L, and 187 × 10⁹ cells/L, respectively, which showed 98.93% similarity with theoretical data. This result could be a premise for further study to improve manufacturing of hematological reference samples for hematology EQA programs.

This study aimed to develop and evaluate simulated leukocytes derived from porcine leukocytes as a stable alternative for internal quality control (IQC) in hematology laboratories. Addressing challenges related to material stability and availability, the research contributes to improving laboratory quality assurance in Vietnam. Statistical methods including Shapiro-Wilk test, Levene's test, t-tests, ANOVA, and the IQR method were applied to assess post-production quality and establish target values. Target values were established from data collected across 90 laboratories. The Interquartile Range (IQR) method was used to eliminate outliers, and target values were set for three analyzers (Sysmex XN-1000, Sysmex XN-550, and Horiba ABX Micros 60) per batch at three concentration levels. Sample stability was evaluated over a two-month shelf life using t-tests and monitored for 20 days post-opening with repeated measures ANOVA. Simulated leukocytes derived from goose erythrocytes exhibited instability at high concentration levels, whereas those derived from porcine leukocytes maintained stability over two months and demonstrated acceptable performance for up to 10 days post-opening. The findings highlight the potential of porcine leukocytes as a reliable IQC material for hematology, meeting the stability and performance requirements of clinical laboratories.