1.Reproducibility of Plasma Biomarker Measurements Across Laboratories:Insights Into ptau217, GFAP, and NfL
Heekyoung KANG ; Sook-Young WOO ; Daeun SHIN ; Sohyun YIM ; Eun Hye LEE ; Hyunchul RYU ; Bora CHU ; Henrik ZETTERBERG ; Kaj BLENNOW ; Jihwan YUN ; Duk L NA ; Hee Jin KIM ; Hyemin JANG ; Jun Pyo KIM ;
Dementia and Neurocognitive Disorders 2025;24(2):91-101
Background:
and Purpose: Plasma biomarkers, including phosphorylated tau (ptau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL), are promising tools for detecting Alzheimer’s disease (AD) pathology. However, cross-laboratory reproducibility remains a challenge, even when using identical analytical platforms such as single-molecule array (Simoa). This study aimed to compare plasma biomarker measurements (ptau217, GFAP, and NfL) between 2 laboratories, the University of Gothenburg (UGOT) and DNAlink, and evaluate their associations with amyloid positron emission tomography (PET) imaging.
Methods:
Plasma biomarkers were measured using Simoa platforms at both laboratories:the UGOT and DNAlink Incorporation. Diagnostic performance for predicting amyloid PET positivity, cross-laboratory agreement, and the impact of normalization techniques were assessed. Bland-Altman plots and correlation analyses were employed to evaluate agreement and variability.
Results:
Plasma ptau217 concentrations exhibited strong correlations with amyloid PET global centiloid values, with comparable diagnostic performance between laboratories (area under the curve=0.94 for UGOT and 0.95 for DNAlink). Cross-laboratory agreement for ptau217 was excellent (r=0.96), improving further after natural log transformation. GFAP and NfL also demonstrated moderate to strong correlations (r=0.86 for GFAP and r=0.99 for NfL), with normalization reducing variability.
Conclusions
Plasma biomarker measurements were consistent across laboratories using identical Simoa platforms, with strong diagnostic performance and improved agreement after normalization. These findings support the scalability of plasma biomarkers for multicenter studies and underscore their potential for standardized applications in AD research and clinical practice.
2.Reproducibility of Plasma Biomarker Measurements Across Laboratories:Insights Into ptau217, GFAP, and NfL
Heekyoung KANG ; Sook-Young WOO ; Daeun SHIN ; Sohyun YIM ; Eun Hye LEE ; Hyunchul RYU ; Bora CHU ; Henrik ZETTERBERG ; Kaj BLENNOW ; Jihwan YUN ; Duk L NA ; Hee Jin KIM ; Hyemin JANG ; Jun Pyo KIM ;
Dementia and Neurocognitive Disorders 2025;24(2):91-101
Background:
and Purpose: Plasma biomarkers, including phosphorylated tau (ptau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL), are promising tools for detecting Alzheimer’s disease (AD) pathology. However, cross-laboratory reproducibility remains a challenge, even when using identical analytical platforms such as single-molecule array (Simoa). This study aimed to compare plasma biomarker measurements (ptau217, GFAP, and NfL) between 2 laboratories, the University of Gothenburg (UGOT) and DNAlink, and evaluate their associations with amyloid positron emission tomography (PET) imaging.
Methods:
Plasma biomarkers were measured using Simoa platforms at both laboratories:the UGOT and DNAlink Incorporation. Diagnostic performance for predicting amyloid PET positivity, cross-laboratory agreement, and the impact of normalization techniques were assessed. Bland-Altman plots and correlation analyses were employed to evaluate agreement and variability.
Results:
Plasma ptau217 concentrations exhibited strong correlations with amyloid PET global centiloid values, with comparable diagnostic performance between laboratories (area under the curve=0.94 for UGOT and 0.95 for DNAlink). Cross-laboratory agreement for ptau217 was excellent (r=0.96), improving further after natural log transformation. GFAP and NfL also demonstrated moderate to strong correlations (r=0.86 for GFAP and r=0.99 for NfL), with normalization reducing variability.
Conclusions
Plasma biomarker measurements were consistent across laboratories using identical Simoa platforms, with strong diagnostic performance and improved agreement after normalization. These findings support the scalability of plasma biomarkers for multicenter studies and underscore their potential for standardized applications in AD research and clinical practice.
3.Reproducibility of Plasma Biomarker Measurements Across Laboratories:Insights Into ptau217, GFAP, and NfL
Heekyoung KANG ; Sook-Young WOO ; Daeun SHIN ; Sohyun YIM ; Eun Hye LEE ; Hyunchul RYU ; Bora CHU ; Henrik ZETTERBERG ; Kaj BLENNOW ; Jihwan YUN ; Duk L NA ; Hee Jin KIM ; Hyemin JANG ; Jun Pyo KIM ;
Dementia and Neurocognitive Disorders 2025;24(2):91-101
Background:
and Purpose: Plasma biomarkers, including phosphorylated tau (ptau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL), are promising tools for detecting Alzheimer’s disease (AD) pathology. However, cross-laboratory reproducibility remains a challenge, even when using identical analytical platforms such as single-molecule array (Simoa). This study aimed to compare plasma biomarker measurements (ptau217, GFAP, and NfL) between 2 laboratories, the University of Gothenburg (UGOT) and DNAlink, and evaluate their associations with amyloid positron emission tomography (PET) imaging.
Methods:
Plasma biomarkers were measured using Simoa platforms at both laboratories:the UGOT and DNAlink Incorporation. Diagnostic performance for predicting amyloid PET positivity, cross-laboratory agreement, and the impact of normalization techniques were assessed. Bland-Altman plots and correlation analyses were employed to evaluate agreement and variability.
Results:
Plasma ptau217 concentrations exhibited strong correlations with amyloid PET global centiloid values, with comparable diagnostic performance between laboratories (area under the curve=0.94 for UGOT and 0.95 for DNAlink). Cross-laboratory agreement for ptau217 was excellent (r=0.96), improving further after natural log transformation. GFAP and NfL also demonstrated moderate to strong correlations (r=0.86 for GFAP and r=0.99 for NfL), with normalization reducing variability.
Conclusions
Plasma biomarker measurements were consistent across laboratories using identical Simoa platforms, with strong diagnostic performance and improved agreement after normalization. These findings support the scalability of plasma biomarkers for multicenter studies and underscore their potential for standardized applications in AD research and clinical practice.
4.Reproducibility of Plasma Biomarker Measurements Across Laboratories:Insights Into ptau217, GFAP, and NfL
Heekyoung KANG ; Sook-Young WOO ; Daeun SHIN ; Sohyun YIM ; Eun Hye LEE ; Hyunchul RYU ; Bora CHU ; Henrik ZETTERBERG ; Kaj BLENNOW ; Jihwan YUN ; Duk L NA ; Hee Jin KIM ; Hyemin JANG ; Jun Pyo KIM ;
Dementia and Neurocognitive Disorders 2025;24(2):91-101
Background:
and Purpose: Plasma biomarkers, including phosphorylated tau (ptau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL), are promising tools for detecting Alzheimer’s disease (AD) pathology. However, cross-laboratory reproducibility remains a challenge, even when using identical analytical platforms such as single-molecule array (Simoa). This study aimed to compare plasma biomarker measurements (ptau217, GFAP, and NfL) between 2 laboratories, the University of Gothenburg (UGOT) and DNAlink, and evaluate their associations with amyloid positron emission tomography (PET) imaging.
Methods:
Plasma biomarkers were measured using Simoa platforms at both laboratories:the UGOT and DNAlink Incorporation. Diagnostic performance for predicting amyloid PET positivity, cross-laboratory agreement, and the impact of normalization techniques were assessed. Bland-Altman plots and correlation analyses were employed to evaluate agreement and variability.
Results:
Plasma ptau217 concentrations exhibited strong correlations with amyloid PET global centiloid values, with comparable diagnostic performance between laboratories (area under the curve=0.94 for UGOT and 0.95 for DNAlink). Cross-laboratory agreement for ptau217 was excellent (r=0.96), improving further after natural log transformation. GFAP and NfL also demonstrated moderate to strong correlations (r=0.86 for GFAP and r=0.99 for NfL), with normalization reducing variability.
Conclusions
Plasma biomarker measurements were consistent across laboratories using identical Simoa platforms, with strong diagnostic performance and improved agreement after normalization. These findings support the scalability of plasma biomarkers for multicenter studies and underscore their potential for standardized applications in AD research and clinical practice.
5.Impact of dietary fiber intake on nonalcoholic fatty liver disease risk in Korean patients with obesity and type 2 diabetes mellitus
Ji-Sook PARK ; Hina AKBAR ; Young-Seol KIM ; Jung-Eun YIM
Journal of Nutrition and Health 2024;57(3):282-291
Purpose:
Korean patients with type 2 diabetes mellitus (T2DM) and obesity are at a high risk of developing severe non-alcoholic fatty liver disease (NAFLD). This study examined the dietary intakes and compared the risks of NAFLD-related complications in Korean patients with T2DM and obesity.
Methods:
Data from the Korean National Diabetes Program cohort were used to study patients with T2DM. Two hundred and sixty-five obese patients with T2DM (body mass index ≥ 25 kg/m2 ) were classified into NAFLD and non-NAFLD groups. The nutrient intake was analyzed using a 24-hour dietary recall questionnaire. Anthropometric and biochemical data were also obtained. Statistical analyses were performed to determine the significant differences between the 2 groups.
Results:
The serum gamma-glutamyl transpeptidase levels in obese patients with T2DM and NAFLD were significantly higher than in obese T2DM patients without NAFLD (p < 0.05). The serum glucose and lipid profiles showed no significant differences between the NAFLD and non-NAFLD groups. The carbohydrate, protein, and fat levels also did not differ significantly. The results showed that the fiber intake of the NAFLD and non-NAFLD groups was 14.11 ± 3.86 g/100 kcal and 15.70 ± 4.56 g/1,000 kcal, respectively, showing that the dietary fiber intake of the non-NAFLD group was significantly higher (p < 0.05). A correlation was observed between total fiber intake and γ-glutamyl transpeptidase in either patient group. In addition, the odds ratio of developing NAFLD was 0.29× lower when the fiber was consumed at 125% of adequate intake.
Conclusions
A higher dietary fiber intake may reduce the risk of NAFLD in obese patients with T2DM. The dietary intake of Korean obese patients with T2DM should include and be enriched in dietary fiber to aid in preventing and treating NAFLD.
6.Core indicators related to the elimination of hepatitis B and C virus infection in South Korea: A nationwide study
Chang Hun LEE ; Gwang Hyeon CHOI ; Hwa Young CHOI ; Sojung HAN ; Eun Sun JANG ; Young Eun CHON ; Young CHANG ; Kyung-Ah KIM ; Do Young KIM ; Hyung Joon YIM ; Hye-Lin KIM ; Sook-Hyang JEONG ; In Hee KIM
Clinical and Molecular Hepatology 2023;29(3):779-793
Background/Aims:
To eliminate hepatitis B virus (HBV) and hepatitis C virus (HCV) according to the World Health Organization (WHO) criteria in 2021, this study investigated the national core indicators representing the current status of viral hepatitis B and C in South Korea.
Methods:
We analyzed the incidence, linkage-to-care, treatment, and mortality rates of HBV and HCV infection using the integrated nationwide big data of South Korea.
Results:
According to data from 2018–2020, the incidence of acute HBV infection in South Korea was 0.71 cases per 100,000 population; tthe linkage-to-care rate was only 39.4%. Among those who need hepatitis B treatment, the treatment rate was 67.3%, which was less than 80% reported in the WHO program index. The annual liver-related mortality due to HBV was 18.85 cases per 100,000 population, exceeding the WHO target of four; the most frequent cause of death was liver cancer (54.1%). The annual incidence of newly diagnosed HCV infection was 11.9 cases per 100,000 population, which was higher than the WHO impact target of five. Among HCV-infected patients, the linkage-to-care rate was 65.5% while the treatment rate was 56.8%, which were below the targets of 90% and 80%, respectively. The liver-related annual mortality rate due to HCV infection was 2.02 cases per 100,000 population.
Conclusions
Many of the current indicators identified in the Korean population did not satisfy the WHO criteria for validation of viral hepatitis elimination. Hence, a comprehensive national strategy should be urgently developed with continuous monitoring of the targets in South Korea.
8.Development and Roll-Out of A Coronavirus Disease 2019 Clinical Pathway for Standardized Qualified Care in Public Hospitals in Korea
Mi Young KWAK ; Eun Young JO ; BumSik CHIN ; Se Eun PARK ; Jun YIM ; Jung Eun LEE ; Kyung Eun JO ; Yeon-Sook KIM ; Jeong Eun LEE ; Young Kyung YOON ; Yu Bin SEO ; Su Jin JEONG ; Yu Min KANG ; Eun-Jeong JOO ; Jong Hyun YOON ; Sun Bean KIM ; Ga Yeon KIM ; Min-Kyung KIM
Infection and Chemotherapy 2022;54(2):353-359
Despite the coronavirus disease 2019 (COVID-19) vaccination roll-out, variant-related outbreaks have occurred repeatedly in Korea. Although public hospitals played a major role in COVID-19 patients’ care, difficulty incorporating evolving COVID-19 treatment guidelines called for a clinical pathway (CP). Eighteen public hospitals volunteered, and a professional review board was created. CPs were formulated containing inclusion/exclusion criteria, application flow charts, and standardized order sets. After CP roll-out, key parameters improved, such as increased patient/staff five-point satisfaction scores (0.41/0.57) and decreased hospital stays (1.78 days)/medical expenses (17.5%). The CPs were updated consistently after roll-out as new therapeutics drugs were introduced and quarantine policies changed.
9.Assessment of dietary quality and nutrient intake of obese children in Changwon area
Ji-Sook PARK ; Ha-Neul CHOI ; Jae-Young KIM ; Sang-Hyuk MA ; Jung-Eun YIM
Journal of Nutrition and Health 2022;55(6):630-641
Purpose:
In this study, we assessed the intake of nutrients and food groups and analyzed the nutrition quotient of obese children in South Korea. The hypothesis was that dietary quality and nutrient intake are related to the body mass index (BMI) of obese children.
Methods:
The participants included 48 children (20 boys and 28 girls). Based on the guidelines for the age-for-body mass index provided by the Korean National Growth Charts for children and adolescents, the participants were divided into 3 groups: overweight, BMI ≥ 85th percentile; obese, BMI ≥ 95th percentile; severely obese, BMI ≥ 99th percentile.
Results:
The energy distribution showed that the carbohydrate ratio was significantly higher in the overweight group (p < 0.01), whereas the fat ratio was significantly higher in the obese and severely obese groups (p < 0.05). Thus, in the overweight and obese groups, the percent body fat was negatively associated with the carbohydrate ratio (p < 0.05) but was positively associated with the fat ratio (p < 0.05). The Dietary Reference Intakes (DRI) data revealed that the intake levels of protein, vitamin B 1 , vitamin B 12 , and sodium were higher in all groups. Intakes of fiber, calcium, potassium, and magnesium were insufficient in all groups, and the DRI percent for protein was significantly higher in the obese and severely obese groups than in the overweight group. No significant differences were obtained in food group patterns or Nutrition Quotient (NQ) scores among the 3 groups. According to the evaluation results by food record and NQ, a significant difference was obtained in the dietary quality of obese children.
Conclusion
We conclude that a higher intake of fat enhances weight gain. Based on the study results, we propose that the guidelines should consider the energy distribution of carbohydrate and fat intake to prevent and control obesity among Korean children.
10.Clinical Characteristics of False-Positive Lymph Node on Chest CT or PET-CT Confirmed by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration in Lung Cancer.
Jongmin LEE ; Young Kyoon KIM ; Ye Young SEO ; Eun Kyoung CHOI ; Dong Soo LEE ; Yeon Sil KIM ; Sook Hee HONG ; Jin Hyoung KANG ; Kyo Young LEE ; Jae Kil PARK ; Sook Whan SUNG ; Hyun Bin KIM ; Mi Sun PARK ; Hyeon Woo YIM ; Seung Joon KIM
Tuberculosis and Respiratory Diseases 2018;81(4):339-346
BACKGROUND: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a standard procedure to evaluate suspicious lymph node involvement of lung cancer because computed tomography (CT) and 18F-fluorodeoxyglucose positron emission tomography-CT (PET-CT) have limitations in their sensitivity and specificity. There are a number of benign causes of false positive lymph node such as anthracosis or anthracofibrosis, pneumoconiosis, old or active tuberculosis, interstitial lung disease, and other infectious conditions including pneumonia. The purpose of this study was to evaluate possible causes of false positive lymph node detected in chest CT or PET-CT. METHODS: Two hundred forty-seven patients who were initially diagnosed with lung cancer between May 2009 and December 2012, and underwent EBUS-TBNA to confirm suspicious lymph node involvement by chest CT or PET-CT were analyzed for the study. RESULTS: Of 247 cases, EBUS-TBNA confirmed malignancy in at least one lymph node in 189. The remaining 58 patients whose EBUS-TBNA results were negative were analyzed. Age ≥65, squamous cell carcinoma as the histologic type, and pneumoconiosis were related with false-positive lymph node involvement on imaging studies such as chest CT and PET-CT. CONCLUSION: These findings suggest that lung cancer staging should be done more carefully when a patient has clinically benign lymph node characteristics including older age, squamous cell carcinoma, and benign lung conditions.
Anthracosis
;
Carcinoma, Squamous Cell
;
Electrons
;
Humans
;
Lung Diseases, Interstitial
;
Lung Neoplasms*
;
Lung*
;
Lymph Nodes*
;
Needles*
;
Pneumoconiosis
;
Pneumonia
;
Sensitivity and Specificity
;
Thorax*
;
Tomography, X-Ray Computed*
;
Tuberculosis

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