1.Considerations of Flow Cytometric Lymphocyte Subset Analysis in Korea Based on a Survey of Current Clinical Laboratory Practice
Mikyoung PARK ; Hyun-Woo CHOI ; Jihyang LIM ; Kyung-Hwa SHIN ; Eun-Jee OH ; Jaewoo SONG ; Kyeong-Hee KIM ; In Hwa JEONG ; Joo-Heon PARK ; Sang-Hyun HWANG ; Eun-Suk KANG
Annals of Laboratory Medicine 2026;46(2):220-225
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 × 10 3 to 5 × 10 4 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.
2.Structural Transformation of the Korean Healthcare System to Protect National Health Rights:From the Perspective of Consumers and Primary Care
Mihwa YOO ; Hee Gyung KANG ; Jae-Heon KANG ; Minjoung KO ; Jong Myoung KIM ; Kunhee PARK ; Serng Bai PAK ; Chiwon SEO ; Junghee AHN ; Juhwan OH ; Eunyoung CHO ; Eun Jin HA
Korean Journal of Family Practice 2026;16(1):9-12
The South Korean healthcare system has achieved rapid quantitative growth; however, it continues to face critical challenges in ensuring the fundamental right to health of its citizens. From the perspective of healthcare consumers and civil society, this article identifies structural problems such as imbalances in medical accessibility, instability in essential and emergency care, and the limited participation of consumers in healthcare policy-making. Although the constitution stipulates the state’s responsibility to protect public health, current healthcare policies often prioritize administrative efficiency and provider-centered interests over patient experiences and health outcomes. In particular, this article argues that these challenges are closely related to the inadequate functioning of an accountable healthcare management framework. Structural failures in essential care, workforce shortages, and regional disparities are insufficiently monitored and addressed at the system level, resulting in responsibilities being blurred or shifted to individual healthcare providers. Consequently, the risks and burdens arising from systemic weaknesses are ultimately borne by citizens. To address these issues, this article emphasizes two major shifts. First, meaningful consumer participation must be institutionalized within healthcare governance to strengthen accountability, transparency, and responsiveness. Second, family medicine and primary care should be reinforced as the cornerstone of a sustainable, community-based healthcare system that ensures continuity of care, prevention, and chronic disease management. Re-establishing the healthcare system based on the right to health is not merely a technical adjustment, but a structural transformation toward a responsible and accountable system in which the state clearly assumes responsibility for monitoring, learning, and corrective action.
3.Transition to a Primary Care–Centered Healthcare System: A Structural Reform for Korean Healthcare
Serng Bai PAK ; Sang-Hyun LEE ; Kyung-Hee CHO ; Juhwan OH ; Sang-il LEE ; Kunhee PARK ; Jae-Heon KANG ; Seung-Won OH ; Hee Gyung KANG ; Mihwa YOO
Korean Journal of Family Practice 2026;16(1):33-41
Korea’s healthcare system is at a critical juncture as rapid population aging, rising chronic disease burdens, and fragmented care expose the limits of a hospital-centered, fee-for-service model. Although policy discussions have long emphasized strengthening primary care and introducing a “family doctor” system, past reforms have focused mainly on expanding services or redefining professional roles, without establishing clear accountability, care continuity, or aligned payment mechanisms. Consequently, primary care remains weak and responsibility for comprehensive patient management is diffuse. This article argues that meaningful reform requires redefining the primary physician as an accountable manager of longitudinal, coordinated care within an integrated delivery and payment framework. Drawing on experiences from the United States, the United Kingdom, and several European countries, it identifies common features of successful primary care–oriented systems, including patient registration, team-based care, risk-adjusted payment, and explicit outcome accountability. Based on these insights, the authors propose a Korean primary physician model tailored to solo and small-group practices while fostering regional collaboration. Core elements include voluntary patient registration, multidisciplinary primary care teams, risk-stratified care management, regional care networks, and a mixed payment model combining per-member-per-month payments, shared savings, and performance-based incentives. The article emphasizes phased pilot testing focused on operational feasibility. Ultimately, transitioning to a primary care–centered system is presented as a strategic necessity for sustainability and improved care continuity.
4.Current Status and Improvement Strategies for the Resident Training System in South Korea:Focusing on Patient Safety and Sustainable Healthcare
Seung-Won OH ; HaDa RYUOK ; Ilyoung OH ; Jae-Heon KANG ; Eun Jin HA ; Hee Gyung KANG ; Serng Bai PAK ; Junghee AHN ; Mihwa YOO ; Eunyoung CHO ; Juhwan OH
Korean Journal of Family Practice 2026;16(1):48-58
The South Korean resident training system is currently at a critical turning point, facing structural crises characterized by excessive labor-intensive environments and deteriorating quality of education. Since the medical standoff in 2024, the limitations of relying on junior doctors’ labor for hospital operations have become increasingly apparent. This review examines the current status and problems of the resident training system, including long working hours exceeding Organisation for Economic Co-operation and Development (OECD) standards, lack of systematic competency-based education, and worsening regional and essential medical imbalances. By analyzing international cases from the United States, United Kingdom, Japan, and Australia, this article proposes four core strategies for reform: (1) establishing a sustainable working and educational environment through the expansion of hospitalist systems and legalizing physician assistant roles; (2) innovating the curriculum and evaluation systems based on entrustable professional activities and milestones; (3) implementing a network-based training model to bridge the gap between metropolitan and regional healthcare; and (4) securing stable financial support and strengthening governance through the establishment of an independent evaluation body (e.g., K-ACGME). Ultimately, reforming the training system is essential not only for the rights and professional growth of residents but also for ensuring patient safety and the long-term sustainability of the national healthcare system.
5.Association of MTUS1 with cisplatin response in head and neck squamous cell carcinoma: a retrospective cohort analysis of The Cancer Genome Atlas data
Eun-Kyong KIM ; Su Young OH ; So-Young CHOI ; Tae-Lyn KIM ; Heon-Jin LEE ; Soyoung KWAK ; Su-Hyung HONG
Journal of Yeungnam Medical Science 2026;43(1):35-
Background:
Cisplatin-based chemotherapy is a mainstay treatment for head and neck squamous cell carcinoma (HNSC); however, resistance to cisplatin contributes substantially to poor clinical outcomes. Identifying biomarkers associated with cisplatin response may improve prognostic assessment and treatment selection.
Methods:
We retrospectively analyzed The Cancer Genome Atlas (TCGA)-HNSC dataset to evaluate the association between microtubule associated scaffold protein 1 (MTUS1) expression and clinical outcomes, with particular emphasis on patients who were cisplatin-treated. Survival analysis was performed using the Kaplan-Meier curves, and differential expression analysis was conducted separately by comparing patients in disease-specific survival (DSS)-living and DSS-deceased groups. MTUS1 messenger RNA and protein levels were examined in cisplatin-sensitive oral cancer cell lines and their paired cisplatin-resistant counterparts using quantitative reverse transcription polymerase chain reaction and western blotting. Functional relevance was assessed by small interfering RNA-mediated MTUS1 knockdown in primary oral squamous cell carcinoma organoids.
Results:
MTUS1 protein expression was significantly lower in HNSC tumors than in non-tumor tissues. In the overall TCGA-HNSC cohort, MTUS1 expression was not significantly associated with survival. However, in patients who were cisplatin-treated, higher MTUS1 expression was significantly associated with more favorable DSS. MTUS1 expression was consistently lower in cisplatin-resistant oral cancer cell lines than in their paired cisplatin-sensitive counterparts. Functional experiments further suggested that reduced MTUS1 expression is associated with decreased cisplatin sensitivity and a resistant phenotype.
Conclusion
MTUS1 expression may be associated with clinical outcomes in patients with cisplatin-treated HNSC and is related to cisplatin responsiveness. These findings suggest a role for MTUS1 as a candidate treatment-relevant biomarker and highlight the value of integrating public omics data with experimental validation.
6.Antibacterial effect of nano-silver coating on implant abutment screw
Chang-Oh LIM ; Jonghyuk LEE ; Hyon-Mo KU ; Dong-Heon BAEK
The Journal of Korean Academy of Prosthodontics 2026;64(1):1-14
Purpose:
. Interfacial microleakage between dental implant and its abutment has been reported as a source of bacteria which can cause peri-implantitis and persistent inflammation, and abutment screw is on the pathway of this contamination. The aim of this study was to evaluate the antibacterial effect of nano-silver coating on the abutment screw against bacteria proliferation.
Materials and methods:
. Titanium abutment screws were coated with silver in nano particle level by sputtering method. The coated screws were examined with SEM and their surface composition were analyzed with EDS. Leakage of metal ions/particle was examined with inductively coupled plasma optical emission spectrometry. To evaluate antibacterial effect, abutment screws with/without coating were contaminated with P. gingivalis, S. sanguinis, T. denticola, T. forsythia for 48 hours. Then their antibacterial effect was evaluated with real-time PCR by comparing the total genomic DNA concentration and 16S rRNA derived cDNA concentration, and effect was confirmed with fluorescent staining technique which enables segregation between live and dead cells.
Results:
. The coating was in even layer with nano sized silver particles (mean particle size 28 nm in diameter) and showed 0.53 µg leakage for 24 hours per screw. The antibacterial effect of the coated group on the tested bacteria resulted in a decrease in the Viable/Total ratio of approximately 86% for P. gingivalis, 89% for S. sanguinis, 61% for T. denticola, and 97% for T. forsythia. The results were statistically significant (P < .05). The microscopic images confirmed anti-bacterial effect of the coated abutment screw.
Conclusion
. Within the limit of this study, nano-silver coating on the abutment screw may damage the viability of P. gingivalis, S. sanguinis, T. denticola, T. forsythia. Silver coating on the titanium abutment screw can be considered as an effective method to give antibacterial effect.
7.Acute Heart Failure Across the Ejection Fraction Spectrum: Phenotypes, Management, and Outcomes From Nationwide KorHF III Registry
Huijin LEE ; Eung Ju KIM ; Seong Woo HAN ; Seong-Mi PARK ; Hyung-Seop KIM ; Myung-Chan CHO ; Hyo-Suk AHN ; Mi-Seung SHIN ; Seok-Jae HWANG ; Jin-Ok JEONG ; Dong Heon YANG ; Junho HYUN ; Jin Oh CHOI ; Hae-Young LEE ; Byung-Su YOO ; Seok-Min KANG ; Dong-Ju CHOI ; Hyun-Jai CHO ;
International Journal of Heart Failure 2026;8(1):43-55
Background and Objectives:
Clinical characteristics and outcomes in acute heart failure (AHF) vary by phenotype. We assessed phenotype-specific features, treatment patterns, and outcomes in a nationwide Korean cohort.
Methods:
The Korean Heart Failure III registry prospectively enrolled 7,351 AHF admissions at 47 hospitals. Among 6,777 patients with available left ventricular ejection fraction (EF), phenotypes were defined as heart failure with reduced EF (HFrEF, ≤40%), mildly reduced EF (HFmrEF,41–49%), or preserved EF (HFpEF, ≥50%). The primary endpoint was a 12-month composite of all-cause death or heart transplantation, evaluated from index admission and, among hospital survivors, from discharge. We used inverse probability weighting (multinomial generalized boosted models with stabilized, trimmed weights) and weighted Cox proportional-hazards models to estimate hazard ratios (HRs).
Results:
Phenotype distribution was 58.9% HFrEF, 13.6% HFmrEF, and 27.5% HFpEF. Crude 12-month composite rates from index admission were 13.4% (HFrEF), 12.7% (HFmrEF), and 16.8% (HFpEF). After weighting, from index admission, HFmrEF (HR, 0.892; 95% confidence interval [CI], 0.731–1.088) and HFpEF (HR, 1.101; 95% CI, 0.939–1.291) did not differ from HFrEF; from discharge, HFpEF had modestly higher risk (HR, 1.207; 95% CI, 1.008–1.445) whereas HFmrEF did not (HR, 1.039; 95% CI, 0.844–1.279). Hyponatremia and chronic kidney disease were consistent adverse markers, while angiotensin-converting enzyme inhibitor/ angiotensin II receptor blocker use at discharge was protective.
Conclusions
Across the EF spectrum, phenotypes showed distinct profiles and risk. Postdischarge risk was modestly higher in HFpEF, supporting phenotype-tailored care and systematic discharge optimization in Korean patients with AHF.
8.Korean Thyroid Association Guidelines on the Management of Differentiated Thyroid Cancers; Part II. Follow-up Surveillance after Initial Treatment 2026
Eun Kyung LEE ; Seung Heon KANG ; Bon Seok KOO ; Mijin KIM ; Min Joo KIM ; Bo Hyun KIM ; Ji Won KIM ; Dong Gyu NA ; Sohyun PARK ; Ji-In BANG ; Kyorim BACK ; Youngduk SEO ; Young-Ik SON ; Young Shin SONG ; Dong Yeob SHIN ; Jong-Hyuk AHN ; Hwa Young AHN ; So Won OH ; Ho-Ryun WON ; Won Sang YOO ; Min Kyoung LEE ; Sang-Woo LEE ; Jeongmin LEE ; Ji Ye LEE ; Dong-Jun LIM ; Ki-Wook CHUNG ; Ari CHONG ; Jin Hyang JUNG ; Sun Wook CHO ; Yoon Young CHO ; Chae Moon HONG ; Young Joo PARK ;
International Journal of Thyroidology 2026;19(1):1-40
In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.
9.Metabolic Phenotypes of Women with Gestational Diabetes Mellitus Affect the Risk of Adverse Pregnancy Outcomes
Joon Ho MOON ; Sookyung WON ; Hojeong WON ; Heejun SON ; Tae Jung OH ; Soo Heon KWAK ; Sung Hee CHOI ; Hak Chul JANG
Endocrinology and Metabolism 2025;40(2):247-257
Background:
Gestational diabetes mellitus (GDM) affects women with diverse pathological phenotypes, but little is known about the effects of this variation on perinatal outcomes. We explored the metabolic phenotypes of GDM and their impact on adverse pregnancy outcomes.
Methods:
Women diagnosed with gestational glucose intolerance or GDM were categorized into subgroups according to their prepregnancy body mass index (BMI) and the median values of the gestational Matsuda and Stumvoll indices. Logistic regression analysis was employed to assess the odds of adverse pregnancy outcomes, such as large-for-gestational age (LGA), small-for-gestational age, preterm birth, low Apgar score, and cesarean section.
Results:
A total of 309 women were included, with a median age of 31 years and a median BMI of 22.3 kg/m2. Women with a higher pre-pregnancy BMI had a higher risk of LGA newborns (adjusted odds ratio [aOR] for pre-pregnancy BMI ≥25 kg/m2 compared to 20–23 kg/m2, 4.26; 95% confidence interval [CI], 1.99 to 9.12; P<0.001; P for trend=0.001), but the risk of other adverse pregnancy outcomes did not differ according to pre-pregnancy BMI. Women with insulin resistance had a higher risk of LGA (aOR, 1.88; 95% CI, 1.02 to 3.47; P=0.043) and cesarean section (aOR, 2.12; 95% CI, 1.29 to 3.50; P=0.003) than women in the insulin-sensitive group. In contrast, defective β-cell function did not affect adverse pregnancy outcomes.
Conclusion
Different metabolic phenotypes of GDM were associated with heterogeneous pregnancy outcomes. Women with obesity and those with insulin resistance are at greater risk of adverse outcomes and might need strict glycemic management during pregnancy.
10.Metabolic Phenotypes of Women with Gestational Diabetes Mellitus Affect the Risk of Adverse Pregnancy Outcomes
Joon Ho MOON ; Sookyung WON ; Hojeong WON ; Heejun SON ; Tae Jung OH ; Soo Heon KWAK ; Sung Hee CHOI ; Hak Chul JANG
Endocrinology and Metabolism 2025;40(2):247-257
Background:
Gestational diabetes mellitus (GDM) affects women with diverse pathological phenotypes, but little is known about the effects of this variation on perinatal outcomes. We explored the metabolic phenotypes of GDM and their impact on adverse pregnancy outcomes.
Methods:
Women diagnosed with gestational glucose intolerance or GDM were categorized into subgroups according to their prepregnancy body mass index (BMI) and the median values of the gestational Matsuda and Stumvoll indices. Logistic regression analysis was employed to assess the odds of adverse pregnancy outcomes, such as large-for-gestational age (LGA), small-for-gestational age, preterm birth, low Apgar score, and cesarean section.
Results:
A total of 309 women were included, with a median age of 31 years and a median BMI of 22.3 kg/m2. Women with a higher pre-pregnancy BMI had a higher risk of LGA newborns (adjusted odds ratio [aOR] for pre-pregnancy BMI ≥25 kg/m2 compared to 20–23 kg/m2, 4.26; 95% confidence interval [CI], 1.99 to 9.12; P<0.001; P for trend=0.001), but the risk of other adverse pregnancy outcomes did not differ according to pre-pregnancy BMI. Women with insulin resistance had a higher risk of LGA (aOR, 1.88; 95% CI, 1.02 to 3.47; P=0.043) and cesarean section (aOR, 2.12; 95% CI, 1.29 to 3.50; P=0.003) than women in the insulin-sensitive group. In contrast, defective β-cell function did not affect adverse pregnancy outcomes.
Conclusion
Different metabolic phenotypes of GDM were associated with heterogeneous pregnancy outcomes. Women with obesity and those with insulin resistance are at greater risk of adverse outcomes and might need strict glycemic management during pregnancy.

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