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.Factors Influencing the Dietary Behavior of Patients with Type 2 Diabetes Mellitus: A Cross-sectional Study
Journal of Korean Academy of Fundamental Nursing 2024;31(1):80-89
Purpose:
This study aimed to identify the factors that affect the dietary behavior of patients with type 2 diabetes mellitus by examining their sociodemographic characteristics, diabetes-related characteristics, and treatment self-regulation.
Methods:
This community-based cross-sectional study was conducted between August and September 2019 at the Hypertension and Diabetes Registration Management Center in South Korea. Data were collected from 109 patients diagnosed with type 2 diabetes using a questionnaire. The data were analyzed using descriptive statistics, the independent t-test, one-way analysis of variance, Pearson correlation coefficients, and multiple regression analysis.
Results:
Among the investigated variables(nutrition education experience, the number of nutrition education sessions, alcohol consumption, autonomous motivation, externally controlled motivation, and amotivation), the number of nutrition education sessions (β=.19, p=.041), alcohol consumption (yes) (β=-.22, p=.014), and autonomous motivation (β=.21, p=.029) influenced patients’ dietary behavior. These factors explained approximately 12% of the total variance.
Conclusion
To improve the dietary behavior of patients with type 2 diabetes, it is crucial to boost their motivation, implement policies on alcohol consumption, and provide ongoing education on nutrition tailored to their needs.
6.Prevalence and Associated Factors of Depression and Anxiety Among Healthcare Workers During the Coronavirus Disease 2019 Pandemic:A Nationwide Study in Korea
Shinwon LEE ; Soyoon HWANG ; Ki Tae KWON ; EunKyung NAM ; Un Sun CHUNG ; Shin-Woo KIM ; Hyun-Ha CHANG ; Yoonjung KIM ; Sohyun BAE ; Ji-Yeon SHIN ; Sang-geun BAE ; Hyun Wook RYOO ; Juhwan JEONG ; NamHee OH ; So Hee LEE ; Yeonjae KIM ; Chang Kyung KANG ; Hye Yoon PARK ; Jiho PARK ; Se Yoon PARK ; Bongyoung KIM ; Hae Suk CHEONG ; Ji Woong SON ; Su Jin LIM ; Seongcheol YUN ; Won Sup OH ; Kyung-Hwa PARK ; Ju-Yeon LEE ; Sang Taek HEO ; Ji-yeon LEE
Journal of Korean Medical Science 2024;39(13):e120-
Background:
A healthcare system’s collapse due to a pandemic, such as the coronavirus disease 2019 (COVID-19), can expose healthcare workers (HCWs) to various mental health problems. This study aimed to investigate the impact of the COVID-19 pandemic on the depression and anxiety of HCWs.
Methods:
A nationwide questionnaire-based survey was conducted on HCWs who worked in healthcare facilities and public health centers in Korea in December 2020. Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) were used to measure depression and anxiety. To investigate factors associated with depression and anxiety, stepwise multiple logistic regression analysis was performed.
Results:
A total of 1,425 participating HCWs were included. The mean depression score (PHQ-9) of HCWs before and after COVID-19 increased from 2.37 to 5.39, and the mean anxiety score (GAD-7) increased from 1.41 to 3.41. The proportion of HCWs with moderate to severe depression (PHQ-9 ≥ 10) increased from 3.8% before COVID-19 to 19.5% after COVID-19, whereas that of HCWs with moderate to severe anxiety (GAD-7 ≥ 10) increased from 2.0% to 10.1%. In our study, insomnia, chronic fatigue symptoms and physical symptoms after COVID-19, anxiety score (GAD-7) after COVID-19, living alone, and exhaustion were positively correlated with depression. Furthermore, post-traumatic stress symptoms, stress score (Global Assessment of Recent Stress), depression score (PHQ-9) after COVID-19, and exhaustion were positively correlated with anxiety.
Conclusion
In Korea, during the COVID-19 pandemic, HCWs commonly suffered from mental health problems, including depression and anxiety. Regularly checking the physical and mental health problems of HCWs during the COVID-19 pandemic is crucial, and social support and strategy are needed to reduce the heavy workload and psychological distress of HCWs.
7.Clinical Outcomes of Solid Organ Transplant Recipients Hospitalized with COVID-19: A Propensity Score-Matched Cohort Study
Jeong-Hoon LIM ; Eunkyung NAM ; Yu Jin SEO ; Hee-Yeon JUNG ; Ji-Young CHOI ; Jang-Hee CHO ; Sun-Hee PARK ; Chan-Duck KIM ; Yong-Lim KIM ; Sohyun BAE ; Soyoon HWANG ; Yoonjung KIM ; Hyun-Ha CHANG ; Shin-Woo KIM ; Juhwan JUNG ; Ki Tae KWON
Infection and Chemotherapy 2024;56(3):329-338
Background:
Solid-organ transplant recipients (SOTRs) receiving immunosuppressive therapy are expected to have worse clinical outcomes from coronavirus disease 2019 (COVID-19). However, published studies have shown mixed results, depending on adjustment for important confounders such as age, variants, and vaccination status.
Materials and Methods:
We retrospectively collected the data on 7,327 patients hospitalized with COVID-19 from two tertiary hospitals with government-designated COVID-19 regional centers. We compared clinical outcomes between SOTRs and non-SOTRs by a propensity score-matched analysis (1:2) based on age, gender, and the date of COVID-19 diagnosis. We also performed a multivariate logistic regression analysis to adjust other important confounders such as vaccination status and the Charlson comorbidity index.
Results:
After matching, SOTRs (n=83) had a significantly higher risk of high-flow nasal cannula use, mechanical ventilation, acute kidney injury, and a composite of COVID-19 severity outcomes than non-SOTRs (n=160) (all P <0.05). The National Early Warning Score was significantly higher in SOTRs than in non-SOTRs from day 1 to 7 of hospitalization ( P for interaction=0.008 by generalized estimating equation). In multivariate logistic regression analysis, SOTRs (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.12–4.11) and male gender (OR, 2.62; 95% CI, 1.26– 5.45) were associated with worse outcomes, and receiving two to three doses of COVID-19 vaccine (OR, 0.43; 95% CI, 0.24–0.79) was associated with better outcomes.
Conclusion
Hospitalized SOTRs with COVID-19 had a worse prognosis than non-SOTRs. COVID-19 vaccination should be implemented appropriately to prevent severe COVID-19 progression in this population.
8.Social and Behavioral Factors Related to Contraception in Korean Adolescents with Sexual Experience: Based on the 2018 and 2021 Korea Youth Risk Behavior Web-Based Survey
Sohyun PARK ; Hong Ji SONG ; Junhee HAN ; Young-Gyun SEO ; Hye-Mi NOH ; Kyung Hee PARK ; Hye-Ji AN ; Yu-Jin PAEK
Korean Journal of Family Practice 2024;14(1):28-39
Background:
Adolescent unintended pregnancies can have detrimental effects on maternal and fetal health, impacting the social lives of young parents. Globally, there is an emphasis on preventing unintended pregnancies in adolescents through comprehensive contraceptive education. This study examined contraception practices and determinants among sexually active Korean adolescents.
Methods:
This study analyzed raw data from the 2018 and 2021 Korea Youth Risk Behavior Survey conducted by the Korea Disease Control and Prevention Agency. The cohort consisted of 6,042 adolescents who reported sexual experience, categorized into those always practicing contraception and those not. We scrutinized factors related to sexual behavior, such as contraception and sex education, as well as other social and behavioral factors.
Results:
Among sexually active adolescents, 47.9% of males and 48.1% of females consistently used contraception. The most prevalent contraceptive method was condoms (male 58.1%; female 59.6%). However, a significant portion of adolescents were not using contraception (male 29.4%; female 21.7%). Females who did not consistently use contraception exhibited higher pregnancy rates (2.4% vs. 11.3%). Consistent contraceptive users tended to live with their families and reported less sexual experience after drinking alcohol. Despite a decline in sexual education in schools from 2018 to 2021, the proportion of adolescents consistently using contraception increased.
Conclusion
To prevent unintended pregnancies among sexually active adolescents, consistent use of appropriate contraceptive methods is crucial.Comprehensive education on contraception should be extended beyond schools to include homes and primary healthcare settings. Policymakers and healthcare providers should consider these consequences when devising strategies to reduce unintended pregnancies among adolescents.
9.Social and Behavioral Factors Related to Contraception in Korean Adolescents with Sexual Experience: Based on the 2018 and 2021 Korea Youth Risk Behavior Web-Based Survey
Sohyun PARK ; Hong Ji SONG ; Junhee HAN ; Young-Gyun SEO ; Hye-Mi NOH ; Kyung Hee PARK ; Hye-Ji AN ; Yu-Jin PAEK
Korean Journal of Family Practice 2024;14(1):28-39
Background:
Adolescent unintended pregnancies can have detrimental effects on maternal and fetal health, impacting the social lives of young parents. Globally, there is an emphasis on preventing unintended pregnancies in adolescents through comprehensive contraceptive education. This study examined contraception practices and determinants among sexually active Korean adolescents.
Methods:
This study analyzed raw data from the 2018 and 2021 Korea Youth Risk Behavior Survey conducted by the Korea Disease Control and Prevention Agency. The cohort consisted of 6,042 adolescents who reported sexual experience, categorized into those always practicing contraception and those not. We scrutinized factors related to sexual behavior, such as contraception and sex education, as well as other social and behavioral factors.
Results:
Among sexually active adolescents, 47.9% of males and 48.1% of females consistently used contraception. The most prevalent contraceptive method was condoms (male 58.1%; female 59.6%). However, a significant portion of adolescents were not using contraception (male 29.4%; female 21.7%). Females who did not consistently use contraception exhibited higher pregnancy rates (2.4% vs. 11.3%). Consistent contraceptive users tended to live with their families and reported less sexual experience after drinking alcohol. Despite a decline in sexual education in schools from 2018 to 2021, the proportion of adolescents consistently using contraception increased.
Conclusion
To prevent unintended pregnancies among sexually active adolescents, consistent use of appropriate contraceptive methods is crucial.Comprehensive education on contraception should be extended beyond schools to include homes and primary healthcare settings. Policymakers and healthcare providers should consider these consequences when devising strategies to reduce unintended pregnancies among adolescents.
10.Social and Behavioral Factors Related to Contraception in Korean Adolescents with Sexual Experience: Based on the 2018 and 2021 Korea Youth Risk Behavior Web-Based Survey
Sohyun PARK ; Hong Ji SONG ; Junhee HAN ; Young-Gyun SEO ; Hye-Mi NOH ; Kyung Hee PARK ; Hye-Ji AN ; Yu-Jin PAEK
Korean Journal of Family Practice 2024;14(1):28-39
Background:
Adolescent unintended pregnancies can have detrimental effects on maternal and fetal health, impacting the social lives of young parents. Globally, there is an emphasis on preventing unintended pregnancies in adolescents through comprehensive contraceptive education. This study examined contraception practices and determinants among sexually active Korean adolescents.
Methods:
This study analyzed raw data from the 2018 and 2021 Korea Youth Risk Behavior Survey conducted by the Korea Disease Control and Prevention Agency. The cohort consisted of 6,042 adolescents who reported sexual experience, categorized into those always practicing contraception and those not. We scrutinized factors related to sexual behavior, such as contraception and sex education, as well as other social and behavioral factors.
Results:
Among sexually active adolescents, 47.9% of males and 48.1% of females consistently used contraception. The most prevalent contraceptive method was condoms (male 58.1%; female 59.6%). However, a significant portion of adolescents were not using contraception (male 29.4%; female 21.7%). Females who did not consistently use contraception exhibited higher pregnancy rates (2.4% vs. 11.3%). Consistent contraceptive users tended to live with their families and reported less sexual experience after drinking alcohol. Despite a decline in sexual education in schools from 2018 to 2021, the proportion of adolescents consistently using contraception increased.
Conclusion
To prevent unintended pregnancies among sexually active adolescents, consistent use of appropriate contraceptive methods is crucial.Comprehensive education on contraception should be extended beyond schools to include homes and primary healthcare settings. Policymakers and healthcare providers should consider these consequences when devising strategies to reduce unintended pregnancies among adolescents.

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