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.Analysis of distress in patients undergoing radical prostatectomy: A multicenter prospective study
Duk Yoon KIM ; Jae Hyun RYU ; Tag Keun YOO ; Yun Beom KIM ; Tae Young JUNG ; Woo Jin KO ; Eun Kyoung YANG
Investigative and Clinical Urology 2024;65(1):40-52
Purpose:
To analyze the degree of psychological distress experienced pre- and postoperatively in patients who underwent radical prostatectomy after being diagnosed with prostate cancer.
Materials and Methods:
Patients diagnosed with prostate cancer who underwent radical prostatectomy without history of psychiatric disorders were included in this study. The degree of psychological distress was evaluated using hospital anxiety and depression scale (HADS) and distress thermometer (DT) questionnaires preoperatively and at 1, 3, 6, and 12 months postoperatively.
Results:
Distress was high preoperatively and decreased over the entire period. In addition, HADS-anxiety and HADS-depression scores showed an improved severity, shifting from an abnormal state to a borderline state in some patients. However, the DT score, including emotional problems, spiritual concerns, physical problems, family problems, and practical problems, was slightly higher at 1 month postoperatively compared to preoperatively. Furthermore, even at 12 months postoperatively, about one fifth of patients surveyed had a DT score of 4 or higher, requiring psychiatric intervention.
Conclusions
Before and after radical prostatectomy, a significant number of patients complained of distress such as anxiety, depression, and insomnia, and they needed help from a specialist because of psychological distress even 12 months postoperatively.Therefore, a close evaluation of the patient’s psychological distress and supportive treatment are needed during the entire pre- and postoperative period.
6.Medication Adherence in Korean Patients with Inflammatory Bowel Disease and Its Associated Factors
Kyunghwan OH ; Eun Ja KWON ; Jeong Hye KIM ; Kyuwon KIM ; Jae Yong LEE ; Hee Seung HONG ; Seung Wook HONG ; Jin Hwa PARK ; Sung Wook HWANG ; Dong-Hoon YANG ; Byong Duk YE ; Jeong-Sik BYEON ; Seung-Jae MYUNG ; Suk-Kyun YANG ; Jeong Yun PARK ; Sang Hyoung PARK
The Ewha Medical Journal 2022;45(2):35-45
Objectives:
It is important that inflammatory bowel disease (IBD) patients adhere to their prescribed medication regimens to avoid the repeat exacerbations, complications, or surgeries associated with this disorder. However, there are few studies on medication adherence in patients with IBD, especially in Asian populations. So, we analyzed the factors associated with medication adherence in Korean IBD patients.
Methods:
Patients who had been diagnosed with Crohn’s disease (CD) or ulcerative colitis (UC) more than 6 months previously and receiving oral medications for IBD were enrolled. Medication adherence was measured using the Medical Adherence Reporting Scale (MARS-5), a self-reported medication adherence measurement tool.
Results:
Among 207 patients in the final study population, 125 (60.4%) had CD and 134 (64.7%) were men. The mean age was 39.63 years (SD, 13.16 years) and the mean disease duration was 10.09 years (SD, 6.33 years). The mean medication adherence score was 22.46 (SD, 2.86) out of 25, and 181 (87.4%) patients had score of 20 or higher.In multiple linear regression analysis, self-efficacy (β=0.341, P<0.001) and ≥3 dosing per day (β=–0.192 P=0.016) were revealed to be significant factors associated with medication adherence. Additionally, there was a positive correlation between self-efficacy and medication adherence (r=0.312, P<0.001). However, disease related knowledge, depression, and anxiety were not significantly associated with medication adherence.
Conclusion
To improve medication adherence among patients with IBD, a reduction in the number of doses per day and an improved self-efficacy will be helpful.
7.Practice Patterns of Korean Urologists Regarding Positive Surgical Margins after Radical Prostatectomy: a Survey and Narrative Review
Jae Hyun RYU ; Yun Beom KIM ; Tae Young JUNG ; Woo Jin KO ; Sun Il KIM ; Dongdeuk KWON ; Duk Yoon KIM ; Tae Hee OH ; Tag Keun YOO
Journal of Korean Medical Science 2021;36(41):e256-
Background:
There is no clear consensus on the optimal treatment with curative intent for patients with positive surgical margins (PSMs) following radical prostatectomy (RP). The aim of this study was to investigate the perceptions and treatment patterns of Korean urologists regarding the resection margin after RP.
Methods:
A preliminary questionnaire was prepared by analyzing various studies on resection margins after RP. Eight experienced urologists finalized the 10-item questionnaire.In July 2019, the final questionnaire was delivered via e-mail to 105 urologists in Korea who specialize in urinary cancers.
Results:
We received replies from 91 of the 105 urologists (86.7%) in our sample population.Among them, 41 respondents (45.1%) had performed more than 300 RPs and 22 (24.2%) had completed 500 or more RPs. In the question about whether they usually performed an additional biopsy beyond the main specimen, to get information about surgical margin invasion during surgery, the main opinion was that if no residual cancer was suspected, it was not performed (74.7%). For PSMs, the Gleason score of the positive site (49.5%) was judged to be a more important prognostic factor than the margin location (18.7%), multifocality (14.3%), or margin length (17.6%). In cases with PSMs after surgery, the prevailing opinion on follow-up was to measure and monitor prostate-specific antigen (PSA) levels rather than to begin immediate treatment (68.1%). Many respondents said that they considered postoperative radiologic examinations when PSA was elevated (72.2%), rather than regularly (24.4%). When patients had PSMs without extracapsular extension (pT2R1) or a negative surgical margin with extracapsular extension (pT3aR0), the response ‘does not make a difference in treatment policy’ prevailed at 65.9%. Even in patients at high risk of PSMs on preoperative radiologic screening, 84.6% of the respondents said that they did not perform neoadjuvant androgen deprivation therapy. Most respondents (75.8%) indicated that they avoided nerve-sparing RP in cases with a high risk of PSMs, but 25.7% said that they had tried nerve-sparing surgery. Additional analyses showed that urologists who had performed 300 or more prostatectomies tended to attempt more nerve-sparing procedures in patients with a high risk of PSMs than less experienced surgeons (36.6% vs. 14.0%; P = 0.012).
Conclusion
The most common response was to monitor PSA levels without recommending any additional treatment when PSMs were found after RP. Through this questionnaire, we found that the perceptions and treatment patterns of Korean urologists differed considerably according to RP resection margin status. Refined research and standard practice guidelines are needed.
8.Continuous quality improvement program and its results of Korean Society for Cytopathology
Yoo-Duk CHOI ; Hoon-Kyu OH ; Su-Jin KIM ; Kyung-Hee KIM ; Yun-Kyung LEE ; Bo-Sung KIM ; Eun-Jeong JANG ; Yoon-Jung CHOI ; Eun-Kyung HAN ; Dong-Hoon KIM ; Younghee CHOI ; Chan-Kwon JUNG ; Sung-Nam KIM ; Kyueng-Whan MIN ; Seok-Jin YOON ; Hun-Kyung LEE ; Kyung Un CHOI ; Hye Kyoung YOON
Journal of Pathology and Translational Medicine 2020;54(3):246-252
Since 1995, the Korean Society for Cytopathology has overseen the Continuous Quality Improvement program for cytopathology laboratories. The Committee of Quality Improvement has carried out an annual survey of cytology data for each laboratory and set standards for proficiency tests. Methods: Evaluations were conducted four times per year from 2008 to 2018 and comprised statistics regarding cytology diagnoses of previous years, proficiency tests using cytology slides provided by the committee, assessment of adequacy of gynecology (GYN) cytology slides, and submission of cytology slides for proficiency tests. Results: A total of 206 institutes participated in 2017, and the results were as follows. The number of cytology tests increased from year to year. The ratio of liquid-based cytology in GYN gradually decreased, as most of the GYN cytology had been performed at commercial laboratories. The distribution of GYN diagnoses demonstrated nearly 3.0% as atypical squamous cells. The rate for squamous cell carcinoma was less than 0.02%. The atypical squamous cell/squamous intraepithelial lesion ratio was about 3:1 and showed an upward trend. The major discordant rate of cytology-histology in GYN cytology was less than 1%. The proficiency test maintained a major discordant rate less than 2%. The rate of inappropriate specimens for GYN cytology slides gradually decreased. Conclusions: The Continuous Quality Improvement program should be included in quality assurance programs. Moreover, these data can contribute to development of national cancer examination guidelines and facilitate cancer prevention and treatment.
9.Erratum to: The KMDS-NATION Study: Korean Movement Disorders Society Multicenter Assessment of Non-Motor Symptoms and Quality of Life in Parkinson's Disease NATION Study Group.
Do Young KWON ; Seong Beom KOH ; Jae Hyeok LEE ; Hee Kyung PARK ; Han Joon KIM ; Hae Won SHIN ; Jinyoung YOUN ; Kun Woo PARK ; Sun Ah CHOI ; Sang Jin KIM ; Seong Min CHOI ; Ji Yun PARK ; Beom S. JEON ; Ji Young KIM ; Sun Ju CHUNG ; Chong Sik LEE ; Jeong Ho PARK ; Tae Beom AHN ; Won Chan KIM ; Hyun Sook KIM ; Sang Myung CHEON ; Hee Tae KIM ; Jee Young LEE ; Ji Sun KIM ; Eun Joo KIM ; Jong Min KIM ; Kwang Soo LEE ; Joong Seok KIM ; Min Jeong KIM ; Jong Sam BAIK ; Ki Jong PARK ; Hee Jin KIM ; Mee Young PARK ; Ji Hoon KANG ; Sook Kun SONG ; Yong Duk KIM ; Ji Young YUN ; Ho Won LEE ; Hyung Geun OH ; Jinwhan CHO ; In Uk SONG ; Young H. SOHN ; Phil Hyu LEE ; Jae Woo KIM
Journal of Clinical Neurology 2017;13(3):315-315
The original version of this article contained wrong informations of some authors which should be changed.
10.Diagnostic Yield and Clinical Impact of Video Capsule Endoscopy in Patients with Chronic Diarrhea: A Korean Multicenter CAPENTRY Study.
Hyun Joo SONG ; Jeong Seop MOON ; Seong Ran JEON ; Jin Oh KIM ; Jinsu KIM ; Dae Young CHEUNG ; Myung Gyu CHOI ; Yun Jeong LIM ; Ki Nam SHIM ; Byong Duk YE ; Jae Hee CHEON ; Cheol Hee PARK ; Hyun Soo KIM ; Ji Hyun KIM ; Dong Kyung CHANG ; Jae Hyuk DO ; Kyeong Ok KIM ; Byung Ik JANG ; Sung Jae SHIN
Gut and Liver 2017;11(2):253-260
BACKGROUND/AIMS: In some cases, chronic diarrhea is unexplained, and small bowel disorders may be one of the causes. The aim of this study was to assess the diagnostic yield and clinical impact of video capsule endoscopy (VCE) in patients with chronic diarrhea. METHODS: We retrospectively analyzed records from October 2002 to August 2013 in the VCE nationwide database registry (n=2,964). Ninety-one patients from 15 medical centers (60 males and 31 females; mean age, 47±19 years) were evaluated for VCE as a result of chronic diarrhea. RESULTS: The duration of chronic diarrhea was 8.3±14.7 months. The positive diagnostic yield of VCE was 42.9% (39/91). However, 15.4% (14/91) exhibited an inconsistent result, and 41.8% (38/91) were negative. Abnormal findings consistent with chronic diarrhea included erosions/aphthous ulcers (19.8%), ulcers (17.6%), mucosal erythema (3.3%), edema (1.1%), and luminal narrowing (1.1%). The most common diagnoses were functional diarrhea associated with irritable bowel syndrome in 37 patients (40.7%) and Crohn’s disease in 18 patients (19.8%). After VCE examination, the diagnosis was changed in 34.1% of the patients (31/91). Hematochezia (odds ratio [OR], 8.802; 95% confidence interval [CI], 2.126 to 36.441) and hypoalbuminemia (OR, 4.811; 95% CI, 1.241 to 18.655) are predictive factors of a positive diagnostic yield. CONCLUSIONS: VCE had a favorable diagnostic yield and clinical impact on the management of patients with chronic diarrhea.
Capsule Endoscopy*
;
Diagnosis
;
Diarrhea*
;
Edema
;
Erythema
;
Female
;
Gastrointestinal Hemorrhage
;
Humans
;
Hypoalbuminemia
;
Irritable Bowel Syndrome
;
Male
;
Phenobarbital
;
Retrospective Studies
;
Ulcer

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