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.Psychosocial Factors Associated With Thoughts Regarding Life-Sustaining Treatment for Oneself and Family Members
Jeewon LEE ; Shin-Gyeom KIM ; Soyoung Irene LEE ; HyunChul YOUN
Psychiatry Investigation 2024;21(6):646-654
Objective:
This study aims to investigate the thoughts of the general population regarding life-sustaining treatment for both oneself and family members and to assess the factors associated with those thoughts.
Methods:
A total of 1,500 individuals participated in this study by completing a questionnaire consisting of self-reporting items with some instructions, basic demographic information, thoughts on life-sustaining treatment, and psychosocial scales. The disease status was calculated using the Charlson Comorbidity Index. The psychosocial scales included the Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), Pittsburgh Sleep Quality Index, and Multidimensional Scale of Perceived Social Support.
Results:
The majority of participants did not want to receive life-sustaining treatment for both themselves and their families. However, more people wanted life-sustaining treatment for their family members (35.9%) than for themselves (21.6%). Among the basic demographic characteristics, there were significant differences in age, sex, marital status, living arrangements, occupational status, religion, and disease status. Regarding the psychosocial scales, there were significant differences in the PHQ-9 and GAD-7 scores between the group that preferred life-sustaining treatment for family members and the group that did not.
Conclusion
The findings suggest that life-sustaining treatment decisions for oneself and for one’s family members can be different. We recommend a more clear expression of one’s preferences regarding the last moments of one’s life, including advance directives.
6.Factors Affecting Stress and Mental Health During the COVID-19 Pandemic
Jinwoo PARK ; Soyoung Irene LEE ; Jeewon LEE ; HyunChul YOUN ; Shin-Gyeom KIM
Psychiatry Investigation 2023;20(2):152-161
Objective:
This study examined the factors influencing the mental health and stress of individuals during the coronavirus disease-2019 (COVID-19) pandemic.
Methods:
A total of 600 participants were enrolled in this anonymous questionnaire survey that included questions on their demographic profiles and experiences related to the COVID-19 pandemic. The COVID-19 Stress Scale for Korean People (CSSK), Warwick– Edinburgh Mental Wellbeing Scale, Generalized Anxiety Disorder-7, Patient Health Questionnaire-9, Insomnia Severity Index, and Multidimensional Scale of Perceived Social Support were used. Data were analyzed using multiple regression to identify the factors affecting the total CSSK scores and the scores of each of the three CSSK subscales.
Results:
Multiple regression analyses revealed that the severity of insomnia, sex, degree of income decline, occupation, religion, education level, marital status, residential status, level of social support, and degree of depression and anxiety had significant relationships with COVID-19-related stress.
Conclusion
We identified factors affecting stress and mental health in the general population during the COVID-19 pandemic. Our findings may be helpful in providing an individualized approach to managing the mental health of the public. We expect that the results of this study will be used to screen high-risk individuals vulnerable to stress and to establish policies related to the public health crisis.
7.A Pilot Study on the Validity and Reliability of Korean School Readiness Inventory on Children With Autism Spectrum Disorder
Hye In JEONG ; Shin-Gyeom KIM ; HyunChul YOUN ; Jeewon LEE ; Soyoung Irene LEE
Psychiatry Investigation 2023;20(10):940-945
Objective:
Successful transition to school is of great importance to children with autism spectrum disorder (ASD). The purpose of this study was to develop a school readiness inventory for Korean children with ASD, and demonstrate its content validity and reliability.
Methods:
The Korean School Readiness Inventory (K-SRI) was developed to assess current levels of some fundamental skills needed for attending school for children with ASD. The K-SRI was comprised of four subscales and 16 test items: Self-help skills, Social and emotional development, School behavior, and Literacy and numeracy skills. For content validity, six experts rated the validity of the test items. Lawshe’s Content Validity Ratio (CVR) was calculated. For reliability, parents of 22 children with ASD entering school completed the KSRI twice. Cronbach’s alpha coefficient was calculated for internal consistency. The test–retest reliability was assessed using the intraclass correlation coefficient (ICC).
Results:
All the items except two items in the literacy and numeracy skills did not show a CVR of 1. The two items were deleted resulting in a 14-item inventory. The Cronbach’s alpha coefficient of the K-SRI was 0.93, showing good internal consistency reliability. The test– retest reliability results showed ICC value of 0.93 (p<0.001), which indicates good stability.
Conclusion
A parent-rated, 14-item school readiness inventory for Korean children with ASD were developed and preliminary evidence of its content validity and reliability were demonstrated in this study. The present study provides a basis for future studies that would further help evaluate and promote school readiness of the children with ASD.
8.The reproducibility of shear wave and strain elastography in epidermal cysts
Ji Na KIM ; Hee Jin PARK ; Myung Sub KIM ; So Yeon WON ; Eunhee SONG ; Minchul KIM ; Hyunchul SHIN
Ultrasonography 2022;41(4):698-705
Purpose:
This study evaluated epidermal cyst elasticity using multiple parameters of strain elastography (SE) and shear wave elastography (SWE) and assessed the reproducibility of each parameter.
Methods:
This retrospective study included 73 patients with epidermal cysts who underwent SE and SWE. SE scores were classified as 1-4 according to elasticity. The strain ratio was evaluated using the elasticity ratio of lesions and adjacent subcutaneous fat tissue. For SWE, the shear wave velocity (m/s), elasticity (kPa) according to the Young modulus, velocity ratio, and elasticity ratio were evaluated. All values were measured twice. The reproducibility of SE and SWE measurements was assessed. The relationships among SE and SWE measurements were evaluated.
Results:
The strain ratio on SE images showed good reproducibility (intra-class correlation coefficient [ICC]=0.789), and SE scores showed substantial reproducibility (kappa=0.753 and kappa=0.758 for readers 1 and 2, respectively). Moderate reproducibility was found for shear wave velocity and elasticity (ICC=0.750 and ICC=0.648, respectively), as well as for the shear wave velocity of the reference tissue and velocity ratio (ICC=0.747 and ICC=0.713, respectively). All SE scores were positively correlated with the strain ratio (P<0.001). The strain ratio in the second SE session was significantly correlated with the elasticity ratio and velocity ratio in the first SWE session (r=0.245, P=0.037; r=0.243, P=0.038, respectively). Other variables were not correlated.
Conclusion
SE and SWE parameters of epidermal cysts showed moderate to good reproducibility. The strain ratio on SE showed good reproducibility and could provide relatively objective and consistent measurements of epidermal cyst elasticity.
9.The Behavioral Effects of Combination Therapy of Memantine and Acetylcholinesterase Inhibitors Compared with Acetylcholinesterase Inhibitors Alone in Patients with Moderate Alzheimer’s Dementia: A Double-Blind Randomized Placebo-Controlled Trial
HyunChul YOUN ; Kang Joon LEE ; Shin-Gyeom KIM ; Seong-Jin CHO ; Woo Jung KIM ; Won Joon LEE ; Jae Yeon HWANG ; Changsu HAN ; Cheolmin SHIN ; Han-yong JUNG
Psychiatry Investigation 2021;18(3):233-240
Objective:
This study aimed to investigate treatment effects of combination therapy of memantine and acetylcholinesterase inhibitors (AchEIs) compared with AchEIs alone on behavioral and psychological symptoms of dementia (BPSD) in patients with moderate Alzheimer’s dementia (AD).
Methods:
This was a 12-week, double-blind, randomized, placebo-controlled trial. A total of 148 patients with moderate AD participated in this study. Mini-Mental State Examination, Neuropsychiatric Inventory (NPI), Clinician’s Interview-Based Impression of Change plus caregiver input, Gottfries–Bråne–Steen Scale, and Zarit Burden Interview were used as assessment scales.
Results:
There were no significant differences in age, sex, or education between AChEIs alone and combination groups. The combination group showed significantly more improvement of NPI-disinhibition score (0.76±2.15) than the AChEIs alone group (-0.14±1.71) after 12 weeks.
Conclusion
Our findings suggest that the combination therapy of memantine and AchEIs might be a beneficial option for reducing disinhibition symptoms of patients with moderate AD compared with AchEIs alone. We believe that clinicians need to consider additional memantine treatment when patients with moderate AD complain disinhibition symptom. A larger clinical trial is needed to further determine the efficacy and advantages of such combination therapy of memantine and AchEIs for treating BPSD of patients with moderate AD.
10.The Behavioral Effects of Combination Therapy of Memantine and Acetylcholinesterase Inhibitors Compared with Acetylcholinesterase Inhibitors Alone in Patients with Moderate Alzheimer’s Dementia: A Double-Blind Randomized Placebo-Controlled Trial
HyunChul YOUN ; Kang Joon LEE ; Shin-Gyeom KIM ; Seong-Jin CHO ; Woo Jung KIM ; Won Joon LEE ; Jae Yeon HWANG ; Changsu HAN ; Cheolmin SHIN ; Han-yong JUNG
Psychiatry Investigation 2021;18(3):233-240
Objective:
This study aimed to investigate treatment effects of combination therapy of memantine and acetylcholinesterase inhibitors (AchEIs) compared with AchEIs alone on behavioral and psychological symptoms of dementia (BPSD) in patients with moderate Alzheimer’s dementia (AD).
Methods:
This was a 12-week, double-blind, randomized, placebo-controlled trial. A total of 148 patients with moderate AD participated in this study. Mini-Mental State Examination, Neuropsychiatric Inventory (NPI), Clinician’s Interview-Based Impression of Change plus caregiver input, Gottfries–Bråne–Steen Scale, and Zarit Burden Interview were used as assessment scales.
Results:
There were no significant differences in age, sex, or education between AChEIs alone and combination groups. The combination group showed significantly more improvement of NPI-disinhibition score (0.76±2.15) than the AChEIs alone group (-0.14±1.71) after 12 weeks.
Conclusion
Our findings suggest that the combination therapy of memantine and AchEIs might be a beneficial option for reducing disinhibition symptoms of patients with moderate AD compared with AchEIs alone. We believe that clinicians need to consider additional memantine treatment when patients with moderate AD complain disinhibition symptom. A larger clinical trial is needed to further determine the efficacy and advantages of such combination therapy of memantine and AchEIs for treating BPSD of patients with moderate AD.

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