https://ir.ymlib.yonsei.ac.kr/handle/22282913/168814 2026-04-15T17:59:26Z https://ir.ymlib.yonsei.ac.kr/handle/22282913/211251 Title: Considerations of Flow Cytometric Lymphocyte Subset Analysis in Korea Based on a Survey of Current Clinical Laboratory Practice Authors: Park, Mikyoung; Choi, Hyun-Woo; Lim, Jihyang; Shin, Kyung-Hwa; Oh, Eun-Jee; Song, Jaewoo; Kim, Kyeong-Hee; Jeong, In Hwa; Park, Joo-Heon; Hwang, Sang-Hyun; Kang, Eun-Suk Abstract: Flow cytometric lymphocyte subset analysis (FCLSA) is essential for assessing immune status across various diseases and clinical settings. We surveyed current clinical laboratory practices related to FCLSA to establish a baseline reference for future standardization in Korea. Nine university hospitals actively performing FCLSA responded to the 22-question survey, which covered seven categories of laboratory practice. These hospitals used commercial reagent antibody kits from either Beckton Dickinson Biosciences (N= 4) or Beckman Coulter Diagnostics (N =5). Most hospitals performed daily instrument setup and scheduled maintenance every 2-6 months. Two levels of commercial quality control materials were routinely used each day. Sample and reagent antibody volumes varied across hospitals, even when the same reagent kit was used. Acquired cell counts ranged from 5 & times; 103 to 5 & times; 104 cells, with two hospitals adjusting counts based on the cell type analyzed. Most laboratories reported percentages and general opinions; some additionally reported white blood cell and lymphocyte counts, along with lymphocyte percentages. This is the first comprehensive survey on the clinical laboratory practice of FCLSA in Korea. Standardization of FCLSA should be accelerated to ensure reliable and reproducible results. 2026-03-01T00:00:00Z https://ir.ymlib.yonsei.ac.kr/handle/22282913/211260 Title: Prevalence and Molecular Epidemiology of Extended-Spectrum β-Lactamase-Producing Escherichia coli and Effects of Antimicrobial Use in Multiple Pig Industry Sectors in Korea Authors: Kim, Young Ah; Kim, Hyunsoo; Seo, Young Hee; Lee, Kyungwon Abstract: Background: The spread of antimicrobial-resistant bacteria has close relationships among humans, animals, and the environment, necessitating the implementation of the "One Health" approach. In previous study, the prevalence and molecular epidemiology of extended-spectrum (3-lactamase-producing Escherichia coli (ESBL-EC) were investigated across multiple pig industry sectors in Korea. In this study, animal developmental stages and antimicrobial usage policies on farms were also considered. Methods: A total of 6,288 non-duplicated samples were collected from pig farms, slaughterhouses, and their personnel from three provinces in Korea between 2020 and 2022. Antimicrobial susceptibility and ESBL gene characterization were performed on the samples. Results: Overall, 1,084 ESBL-EC isolates were collected, with positivity detection rates of 24.7%, 23.3%, 12.7%, 3.9%, 17.2% in pigs, workers, the environment, meat, and total samples, respectively. Common ESBL types were blaCTX-M-55 (N = 628), blaCTX-M-15 (N = 204), and blaCTX-M-14 (N =127). Pig-derived E. coli isolates had antimicrobial resistance (AMR) rates of 80.4%, 47.2%, 32.6%, 36.7%, 43.4%, 62.4%, and 72.1% to ampicillin, piperacillin, cefazoline, ciprofloxacin, cotrimoxazole, chloramphenicol, and tetracycline, respectively. AMR rates were lower in the finishing stage pigs than in the lactating stage pigs and tended to decrease during animal development for most antimicrobials. AMR rates were higher in pigfarms with a customary antimicrobial use policy than in those with a low-level antimicrobial use policy. Conclusions: The findings highlight the significance of elucidating AMR networks among humans, animals, and the environment. Prudent antimicrobial usage and continuous AMR monitoring in the pig industry are crucial to safeguard food safety. 2026-03-01T00:00:00Z https://ir.ymlib.yonsei.ac.kr/handle/22282913/211254 Title: Development and Performance Validation of a Comprehensive Liquid Biopsy Genotyping Panel for Pan-cancer Analysis Authors: Lim, Seoyoung; Lee, Kwang Seob; Won, Dongju; Seo, Sung Hyun; Lee, Seung-Tae; Choi, Jong Rak; Seo, Jieun; Shin, Saeam; 이광섭 Abstract: Background: Precision oncology is advancing, increasing the demand for comprehensive, non-invasive genomic profilingtools. Liquid biopsy using circulatingtumor DNA (ctDNA) enables real-time molecular profiling, treatment monitoring, and early detection of resistance variants. We developed the PAN100 panel (Dxome), a hybridization capture panel targeting 101 genes, as a pan-cancer genotyping assay to detect clinically actionable variants across various cancer types. This study presents the first comprehensive validation of the PAN100 panel including both analytical and clinical performance across eight cancer types using reference materials and matched tissue samples. Methods: For analytical validation, we assessed accuracy, limit of detection (LoD), and precision using Seraseq ctDNA v2 Reference Materials (SeraCare, Milford, MA, USA). Clinical validation was performed using plasma samples from 27 patients with eight types of cancer and 17 matched tumor samples. Positive percent agreement (PPA) between ctDNA and tissue next-generation sequencing (NGS) results was assessed using TruSight Oncology 500 and TruSight Tumor 170 assays. The limit of blank (LoB) was evaluated in 34 healthy individuals. Results: The PAN100 panel demonstrated high precision and linearity (LoD, 0.3%; 95.0% confidence interval, 0.29-0.35) variant allele frequency. The PPA between ctDNA and tissue NGS was 73.1% for single-nucleotide variants, 80.0% for insertions/deletions, and 74.2% overall. The LoB was 0.00001%. Conclusions: The PAN100 panel is a robust tool for detecting clinically significant variants with high concordance with tissue NGS. Its sensitivity for low-frequency variants enables real-time treatment adaptation, supporting precision oncology. Its comprehensive design is particularly valuable for challenging diagnoses and clonal evolution monitoring. 2026-03-01T00:00:00Z https://ir.ymlib.yonsei.ac.kr/handle/22282913/211667 Title: Comparative Evaluation of Four Multiple Allergen Simultaneous Test (MAST) Systems in Clinical Practice Authors: Lee, Sojin; Song, Junhyup; Lee, Kyung-A; Park, Younhee; 이소진 Abstract: Purpose: Multiple allergen simultaneous tests (MASTs) are widely used for screening allergen-specific immunoglobulin E owing to their convenience and cost-effectiveness. Recently, several automated MAST analyzers with expanded allergen panels have become available in Korea; however, comparative evaluations remain limited. Patients and Methods: In this retrospective study, 200 residual serum samples from patients tested for suspected allergic diseases at a single tertiary hospital were analyzed. Each sample was tested using AdvanSure Alloscreen, AdvanSure Alloscreen Max108, SGTi-Allergy Screen, and PROTIA Allergy-Q. Semi-quantitative results (classes 0-6) were interpreted as positive at class >= 2. Concordance rates and Cohen's kappa coefficients were calculated. Results: Overall agreement between the MAST systems was high (91-93%), with Cohen's kappa values indicating substantial to almost perfect agreement (kappa = 0.67-0.76). The agreement between AdvanSure Alloscreen and its upgraded version, AdvanSure AlloScreen Max108, was the highest. For common allergens in the Korean population, Dermatophagoides pteronyssinus and Dermatophagoides farinae showed moderate agreement (kappa = 0.47-0.82, respectively) between the MAST systems. Re-testing of discrepant samples (n = 78; 31 allergens) using ImmunoCAP-often considered the gold standard for allergy testing-demonstrated the highest concordance for the SGTi Allergy Screen (76.39%). Conclusion: All four MAST systems demonstrated substantial to near-perfect qualitative agreement. The SGTi-Allergy Screen showed the best concordance with ImmunoCAP, whereas AdvanSure Alloscreen Max108 offered a balanced performance with broader allergen coverage. These findings indicate that laboratories should select a MAST system based on local needs, weighing analytical accuracy, allergen panel breadth, and overall testing efficiency. Plain Language Summary: Allergies are becoming more common around the world, and laboratory tests are commonly used to support the evaluation of allergic sensitization in clinical practice. One of these tests is called the Multiple Allergen Simultaneous Test (MAST), which can detect antibodies in the blood that react to many different allergens at once. Because several different MAST systems are used in clinical practice, it is important to understand how similar their results are and how they compare with one another. In this study, we compared four commonly used MAST systems by testing blood samples for common airborne and food allergens, such as house dust mites, pollen, and nuts. We examined how closely the test results agreed across systems and rechecked some inconsistent results using another laboratory method called ImmunoCAP, which is often used as a reference test. We found that the four MAST systems produced broadly similar results overall, although differences were observed for certain plant-based allergens. Among the systems, the SGTi-Allergy Screen showed the closest agreement with the reference test, while the AdvanSure Alloscreen Max108 offered a wider range of allergens in a single test. These findings can help clinicians better understand the strengths of each system and make informed choices when selecting a MAST system for routine testing. 2026-03-01T00:00:00Z