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.Validation of prediction model for successful discontinuation of continuous renal replacement therapy: a multicenter cohort study
Junseok JEON ; Eun Jeong KO ; Hyejeong PARK ; Song In BAEG ; Hyung Duk KIM ; Ji-Won MIN ; Eun Sil KOH ; Kyungho LEE ; Danbee KANG ; Juhee CHO ; Jung Eun LEE ; Wooseong HUH ; Byung Ha CHUNG ; Hye Ryoun JANG
Kidney Research and Clinical Practice 2024;43(4):528-537
Continuous renal replacement therapy (CRRT) has become the standard modality of renal replacement therapy (RRT) in critically ill patients. However, consensus is lacking regarding the criteria for discontinuing CRRT. Here we validated the usefulness of the prediction model for successful discontinuation of CRRT in a multicenter retrospective cohort. Methods: One temporal cohort and four external cohorts included 1,517 patients with acute kidney injury who underwent CRRT for >2 days from 2018 to 2020. The model was composed of four variables: urine output, blood urea nitrogen, serum potassium, and mean arterial pressure. Successful discontinuation of CRRT was defined as the absence of an RRT requirement for 7 days thereafter. Results: The area under the receiver operating characteristic curve (AUROC) was 0.74 (95% confidence interval, 0.71–0.76). The probabilities of successful discontinuation were approximately 17%, 35%, and 70% in the low-score, intermediate-score, and highscore groups, respectively. The model performance was good in four cohorts (AUROC, 0.73–0.75) but poor in one cohort (AUROC, 0.56). In one cohort with poor performance, attending physicians primarily controlled CRRT prescription and discontinuation, while in the other four cohorts, nephrologists determined all important steps in CRRT operation, including screening for CRRT discontinuation. Conclusion: The overall performance of our prediction model using four simple variables for successful discontinuation of CRRT was good, except for one cohort where nephrologists did not actively engage in CRRT operation. These results suggest the need for active engagement of nephrologists and protocolized management for CRRT discontinuation.
6.Correction: 2023 Korean Society of Echocardiography position paper for diagnosis and management of valvular heart disease, part I: aortic valve disease
Sun Hwa LEE ; Se Jung YOON ; Byung Joo SUN ; Hyue Mee KIM ; Hyung Yoon KIM ; Sahmin LEE ; Chi Young SHIM ; Eun Kyoung KIM ; Dong Hyuk CHO ; Jun Bean PARK ; Jeong Sook SEO ; Jung Woo SON ; In Cheol KIM ; Sang Hyun LEE ; Ran HEO ; Hyun Jung LEE ; Jae Hyeong PARK ; Jong Min SONG ; Sang Chol LEE ; Hyungseop KIM ; Duk Hyun KANG ; Jong Won HA ; Kye Hun KIM ;
Journal of Cardiovascular Imaging 2024;32(1):34-
7.Contemporary diagnosis and treatment of valvular heart disease in Korea: a nationwide hospital‑based registry study
Hyung Yoon KIM ; Hee Jeong LEE ; In‑Cheol KIM ; Jung‑Woo SON ; Jun‑Bean PARK ; Sahmin LEE ; Eun Kyoung KIM ; Seong‑Mi PARK ; Woo‑Baek CHUNG ; Jung Sun CHO ; Jin‑Sun PARK ; Jeong‑Sook SEO ; Sun Hwa LEE ; Byung Joo SUN ; Chi Young SHIM ; Hyungseop KIM ; Kye Hun KIM ; Duk‑Hyun KANG ; Jong‑Won HA ;
Journal of Cardiovascular Imaging 2024;32(1):37-
Background:
This study was designed to determine the current status of diagnosis and treatment of valvular heart disease (VHD) in Korea.
Methods:
A nationwide registry study was conducted in 45 hospitals in Korea involving adult patients with at least moderate VHD as determined by echocardiography carried out between September and October of 2019. Of a total of 4,094 patients with at least moderate VHD, 1,482 had severe VHD (age, 71.3 ± 13.5 years; 49.1% male). Echocar‑ diographic data used for the diagnosis of each case of VHD were analyzed. Experts from each center determined the diagnosis and treatment strategy for VHD based on current guidelines and institutional policy. The clinical out‑ come was in-hospital mortality.
Results:
Each valve underwent surgical or transcatheter intervention in 19.3% cases of severe mitral stenosis, 31.4% cases of severe primary mitral regurgitation (MR), 7.5% cases of severe secondary MR, 43.7% cases of severe aortic stenosis, 27.5% cases of severe aortic regurgitation, and 7.2% cases of severe tricuspid regurgitation. The overall inhospital mortality rate for patients with severe VHD was 5.4%, and for secondary severe MR and severe tricuspid regur‑ gitation, the rates were 9.0% and 7.5%, respectively, indicating a poor prognosis. In-hospital mortality occurred in 73 of the 1,244 patients (5.9%) who received conservative treatment and in 18 of the 455 patients (4.0%) who received a surgical or transcatheter intervention, which was significantly lower in the intervention group (P = 0.037).
Conclusions
This study provides important information about the current status of VHD diagnosis and treatment through a nationwide registry in Korea and helps to define future changes.
8.Clinical Manifestations and Outcomes of Older Patients with COVID-19: A Comprehensive Review
Jeong Eun LEE ; Da Hyun KANG ; So-Yun KIM ; Duk Ki KIM ; Song I LEE
Tuberculosis and Respiratory Diseases 2024;87(2):145-154
The consequences of coronavirus disease 2019 (COVID-19) are particularly severe in older adults with a disproportionate number of severe and fatal outcomes. Therefore, this integrative review aimed to provide a comprehensive overview of the clinical characteristics, management approaches, and prognosis of older patients diagnosed with COVID-19. Common clinical presentations in older patients include fever, cough, and dyspnea. Additionally, preexisting comorbidities, especially diabetes and pulmonary and cardiovascular diseases, were frequently observed and associated with adverse outcomes. Management strategies varied, however, early diagnosis, vigilant monitoring, and multidisciplinary care were identified as key factors for enhancing patient outcomes. Nonetheless, the prognosis remains guarded for older patients, with increased rates of hospitalization, mechanical ventilation, and mortality. However, timely therapeutic interventions, especially antiviral and supportive treatments, have demonstrated some efficacy in mitigating the severe consequences in this age group. In conclusion, while older adults remain highly susceptible to severe outcomes from COVID-19, early intervention, rigorous monitoring, and comprehensive care can play a pivotal role in improving their clinical outcomes.
9.Correction: 2023 Korean Society of Echocardiography position paper for diagnosis and management of valvular heart disease, part I: aortic valve disease
Sun Hwa LEE ; Se Jung YOON ; Byung Joo SUN ; Hyue Mee KIM ; Hyung Yoon KIM ; Sahmin LEE ; Chi Young SHIM ; Eun Kyoung KIM ; Dong Hyuk CHO ; Jun Bean PARK ; Jeong Sook SEO ; Jung Woo SON ; In Cheol KIM ; Sang Hyun LEE ; Ran HEO ; Hyun Jung LEE ; Jae Hyeong PARK ; Jong Min SONG ; Sang Chol LEE ; Hyungseop KIM ; Duk Hyun KANG ; Jong Won HA ; Kye Hun KIM ;
Journal of Cardiovascular Imaging 2024;32(1):34-
10.Contemporary diagnosis and treatment of valvular heart disease in Korea: a nationwide hospital‑based registry study
Hyung Yoon KIM ; Hee Jeong LEE ; In‑Cheol KIM ; Jung‑Woo SON ; Jun‑Bean PARK ; Sahmin LEE ; Eun Kyoung KIM ; Seong‑Mi PARK ; Woo‑Baek CHUNG ; Jung Sun CHO ; Jin‑Sun PARK ; Jeong‑Sook SEO ; Sun Hwa LEE ; Byung Joo SUN ; Chi Young SHIM ; Hyungseop KIM ; Kye Hun KIM ; Duk‑Hyun KANG ; Jong‑Won HA ;
Journal of Cardiovascular Imaging 2024;32(1):37-
Background:
This study was designed to determine the current status of diagnosis and treatment of valvular heart disease (VHD) in Korea.
Methods:
A nationwide registry study was conducted in 45 hospitals in Korea involving adult patients with at least moderate VHD as determined by echocardiography carried out between September and October of 2019. Of a total of 4,094 patients with at least moderate VHD, 1,482 had severe VHD (age, 71.3 ± 13.5 years; 49.1% male). Echocar‑ diographic data used for the diagnosis of each case of VHD were analyzed. Experts from each center determined the diagnosis and treatment strategy for VHD based on current guidelines and institutional policy. The clinical out‑ come was in-hospital mortality.
Results:
Each valve underwent surgical or transcatheter intervention in 19.3% cases of severe mitral stenosis, 31.4% cases of severe primary mitral regurgitation (MR), 7.5% cases of severe secondary MR, 43.7% cases of severe aortic stenosis, 27.5% cases of severe aortic regurgitation, and 7.2% cases of severe tricuspid regurgitation. The overall inhospital mortality rate for patients with severe VHD was 5.4%, and for secondary severe MR and severe tricuspid regur‑ gitation, the rates were 9.0% and 7.5%, respectively, indicating a poor prognosis. In-hospital mortality occurred in 73 of the 1,244 patients (5.9%) who received conservative treatment and in 18 of the 455 patients (4.0%) who received a surgical or transcatheter intervention, which was significantly lower in the intervention group (P = 0.037).
Conclusions
This study provides important information about the current status of VHD diagnosis and treatment through a nationwide registry in Korea and helps to define future changes.

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