Raúl Rigo-Bonnin, Estel Julià-Quiñones, Anna Escalante-Vilanova, Irene Aliart-Fernández
{"title":"Are vitamins A and E results truly traceable and clinically useful? A practical and critical inquiry.","authors":"Raúl Rigo-Bonnin, Estel Julià-Quiñones, Anna Escalante-Vilanova, Irene Aliart-Fernández","doi":"10.1515/cclm-2025-0714","DOIUrl":"https://doi.org/10.1515/cclm-2025-0714","url":null,"abstract":"","PeriodicalId":10390,"journal":{"name":"Clinical chemistry and laboratory medicine","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144945322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anne Stavelin, Eva Rønneseth, Anne Lise Fossum, Stein Binder, Camilla Aker, Maria Kim Nguyen, Sverre Sandberg
{"title":"Quality assurance using patient split samples: recommendations for primary healthcare laboratories.","authors":"Anne Stavelin, Eva Rønneseth, Anne Lise Fossum, Stein Binder, Camilla Aker, Maria Kim Nguyen, Sverre Sandberg","doi":"10.1515/cclm-2025-0818","DOIUrl":"https://doi.org/10.1515/cclm-2025-0818","url":null,"abstract":"<p><strong>Objectives: </strong>The increasing adoption of point-of-care testing (POCT) in primary healthcare highlights the need for robust quality assurance (QA) procedures to ensure result reliability. The patient split sample approach, i.e. comparing POCT and central laboratory results from the same patient, can be a valuable QA tool, though practical guidance for its implementation remains scarce. This study aimed to develop clear, user-friendly recommendations for non-laboratory personnel in primary healthcare laboratories on when and how to perform such comparisons and to recommend acceptable limits for the compared results.</p><p><strong>Methods: </strong>In 2023, an expert group was established, composed of medical specialists in laboratory medicine, researchers, and laboratory advisors. The recommendations were formulated based on relevant literature, the professional experience of the group members, and Noklus' educational framework for primary care laboratories. Pragmatic acceptability limits were established taking several approaches into account. The draft recommendations were audited among more than 120 Noklus employees and final consensus was reached in 2024.</p><p><strong>Results: </strong>Comparing POCT results with central laboratory results is recommended when: (A) no suitable EQA program exists for a given POCT; (B) appropriate internal quality control materials are lacking or inadequate; or (C) POCT results contradict clinical expectations. Acceptable limits for the compared results were set at 15 or 20 %, depending on the measurand. Results outside these limits should be reviewed using a structured checklist.</p><p><strong>Conclusions: </strong>These are the first published recommendations for using patient split samples in primary healthcare that are designed to be simple and user-friendly for non-laboratory personnel, facilitating widespread adoption.</p>","PeriodicalId":10390,"journal":{"name":"Clinical chemistry and laboratory medicine","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144945292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Age distorts the interpretation of FIB-4.","authors":"Arne Åsberg, Gunhild Garmo Hov, Lena Løfblad","doi":"10.1515/cclm-2025-0615","DOIUrl":"https://doi.org/10.1515/cclm-2025-0615","url":null,"abstract":"<p><strong>Objectives: </strong>To determine whether the diagnostic accuracy of the liver fibrosis marker FIB-4 and the likelihood ratios (LRs) of specific FIB-4 values vary with age.</p><p><strong>Methods: </strong>We used a published dataset of 540 patients diagnosed with non-alcoholic fatty liver disease (NAFLD) or non-alcoholic steatohepatitis. Liver biopsy showed no or early fibrosis in 391 patients, and advanced fibrosis in 149. For each group we established the relation between the mean of the natural logarithm of FIB-4 (log(FIB-4)) and age, and the standard deviation (SD) of log(FIB-4) and age. Using a parametric method, we calculated the area under the ROC curve of FIB-4 as a function of the difference in mean values of log(FIB-4) between the two groups, and the ratio of the SDs of log(FIB-4). LRs were calculated as functions of age at 35, 50 and 65 years, using a parametric method.</p><p><strong>Results: </strong>The mean log(FIB-4) increased with age in both groups. The SDs of log(FIB-4) did not change with age. There was a trend towards decreasing diagnostic accuracy with age, but this finding did not reach statistical significance. The area under the ROC curve was 0.73 using a parametric method that accounted for age, and 0.79 using a traditional non-parametric method that did not account for age. The LRs of specific FIB-4 values decreased with age.</p><p><strong>Conclusions: </strong>Age distorts the estimation of both diagnostic accuracy and LRs.</p>","PeriodicalId":10390,"journal":{"name":"Clinical chemistry and laboratory medicine","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144945372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An innovative immunoassay for accurate aldosterone quantification: overcoming low-level inaccuracy and renal dysfunction-associated interference.","authors":"Kaijuan Wang, Hongying Cong, Zhangwei Gao, Xiaojing Gao, Wei Zhang, Xiaocui Shi, Zhou Zhou","doi":"10.1515/cclm-2025-0743","DOIUrl":"https://doi.org/10.1515/cclm-2025-0743","url":null,"abstract":"<p><strong>Objectives: </strong>Accurate quantification of aldosterone is critical for screening and diagnosing primary aldosteronism (PA). Current competitive chemiluminescence immunoassays (cCLIA) overestimate plasma aldosterone concentration (PAC) compared to liquid chromatography-tandem mass spectrometry (LC-MS/MS). However, LC-MS/MS is technically demanding and time-consuming, limiting its widespread clinical utility. Therefore, a novel two-step sandwich chemiluminescence immunoassay (sCLIA) for accurate quantification of PAC was systematically evaluated.</p><p><strong>Methods: </strong>Precision, trueness, linear range, and maximum dilution factor of the new immunoassay were comprehensively validated. In a multicenter study involving 2,696 samples from seven Chinese centers, PAC measurements were performed in parallel using sCLIA, cCLIA, and LC-MS/MS. The study specifically focused on evaluating the assay's performance at low aldosterone concentrations and in patients with chronic kidney disease (CKD), investigating potential interference from renal impairment by comparing the consistency between immunoassays and LC-MS/MS results across different CKD stages.</p><p><strong>Results: </strong>The sCLIA exhibited excellent analytical performance for PAC measurement, with intra-assay imprecision <4.64 % and bias <5.71 % against certificated reference materials. The assay exhibited a wide reportable range (30-100,000 ng/L) with a limit of quantification at 30 ng/L and dilution capability ≥50-fold. Compared to cCLIA, sCLIA showed superior agreement with LC-MS/MS, particularly at low PAC concentrations (<110 ng/L) and in subjects with reduced renal function (eGFR<60 mL/min/1.73 m<sup>2</sup>).</p><p><strong>Conclusions: </strong>This novel sCLIA method exhibited excellent analytical performance, combining the practical advantages of immunoassays with LC-MS/MS accuracy, thereby offering an ideal solution for large-scale primary aldosteronism screening in clinical practice.</p>","PeriodicalId":10390,"journal":{"name":"Clinical chemistry and laboratory medicine","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144945289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Burak Arslan, Ulf Andreasson, Elzbieta Rembeza, Markus Axelsson, Lenka Novakova, Bjørn-Eivind Kirsebom, Tormod Fladby, Anna Dittrich, Silke Kern, Ingmar Skoog, Kaj Blennow, Henrik Zetterberg, Hlin Kvartsberg
{"title":"Validation of a plasma GFAP immunoassay and establishment of age-related reference values: bridging analytical performance and routine implementation.","authors":"Burak Arslan, Ulf Andreasson, Elzbieta Rembeza, Markus Axelsson, Lenka Novakova, Bjørn-Eivind Kirsebom, Tormod Fladby, Anna Dittrich, Silke Kern, Ingmar Skoog, Kaj Blennow, Henrik Zetterberg, Hlin Kvartsberg","doi":"10.1515/cclm-2025-0870","DOIUrl":"https://doi.org/10.1515/cclm-2025-0870","url":null,"abstract":"<p><strong>Objectives: </strong>Glial fibrillary acidic protein (GFAP) is a well-established biomarker of astrocytic activation associated with neurodegenerative diseases, neuroinflammatory disorders, and traumatic brain injury. With increasing interest in blood-based biomarkers, the need for analytically validated assays and reliable reference intervals is critical for routine clinical implementation. This study aimed to analytically validate the MSD S-Plex<sup>®</sup> GFAP immunoassay for plasma and to establish age-stratified reference intervals in an apparently healthy population.</p><p><strong>Methods: </strong>This study was conducted in two phases. First, key analytical validation parameters - including repeatability, intermediate precision, measurement range, interferences, and sample stability - were evaluated following Clinical and Laboratory Standards Institute (CLSI) and published protocol guidelines. Second, reference intervals were derived from 579 apparently healthy individuals aged 17-91 years using a right-sided non-parametric percentile method. Age-specific upper reference limits were calculated for three predefined age groups, and a continuous age-dependent centile model was applied.</p><p><strong>Results: </strong>MSD S-Plex<sup>®</sup> GFAP assay demonstrated strong analytical performance, with coefficients of variation for repeatability and intermediate precision below 12 %. After accounting for the 1:2 dilution ratio, the validated measurement range was 0.425-1760 ng/L, with all calibration residuals remaining within ±15 %. GFAP concentrations were unaffected by hemolysis (p=0.85) and remained stable for up to 7 days at 4 °C and under frozen storage conditions. Age-stratified upper reference limits for plasma GFAP were established as 38 pg/mL (18-<50 years), 73 pg/mL (≥50-<70 years), and 156 pg/mL (≥70 years). Additionally, sex-related differences were observed after age 50, with females showing higher absolute GFAP levels than males. A strong positive correlation between age and plasma GFAP levels was observed (Spearman's r=0.832, p<0.0001).</p><p><strong>Conclusions: </strong>This study demonstrates the robust analytical performance of the MSD S-Plex<sup>®</sup> GFAP assay and establishes age-related reference values for plasma GFAP. These findings support its suitability for routine clinical use and enhance its applicability in the diagnosis and monitoring of central nervous system (CNS) pathologies, such as neurodegenerative diseases, neuroinflammatory disorders, and acute brain injuries, within biomarker-supported clinical algorithms.</p>","PeriodicalId":10390,"journal":{"name":"Clinical chemistry and laboratory medicine","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144944950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An automatic chemiluminescence immunoassay for a novel biomarker NT-IGFBP-4: analytical performance and clinical relevance in heart failure.","authors":"Shuzheng Cao, Jing Wang, Ling Li, Yu Wu, Juan Yang, Litao Zhang, Xin Shu, Hui Wang, Yisha Jing, Yi Zhang, Zhenlu Zhang","doi":"10.1515/cclm-2025-0378","DOIUrl":"https://doi.org/10.1515/cclm-2025-0378","url":null,"abstract":"<p><strong>Objectives: </strong>Insulin-like growth factor binding protein-4 (IGFBP-4) fragments are reported as emerging biomarkers for cardiovascular disease (CVD) risk assessment. To ensure data reliability and improve clinical application, the first automatic chemiluminescent immunoassay (CLIA) for NT-IGFBP-4 was developed and its distribution across CVDs was evaluated in this study.</p><p><strong>Methods: </strong>Fragment-specific monoclonal antibodies were used to develop immunoassay, followed by comprehensive analytical validation, including limit of blank (LoB), limit of detection (LoD), limit of quantification (LoQ), linearity, specificity, precision, sample type compatibility, and stability. Reference intervals for NT-IGFBP-4 were established in healthy individuals, with variations analyzed based on gender, age, body mass index (BMI), and renal function. Additionally, NT-IGFBP-4 distribution was explored in CVD patients.</p><p><strong>Results: </strong>The newly developed chemiluminescence assay demonstrated high specificity for NT-IGFBP-4, with excellent sensitivity (LoQ=1.0 ng/mL), broad linearity (1.0-1,000.0 ng/mL), and strong precision (CV≤3.0 %). It showed no interference from common endogenous substances, maintained compatible with various sample types, and remained stable under different storage conditions. Reference intervals showed slight variations by gender and age, with levels being independent of BMI but influenced by renal function. NT-IGFBP-4 levels were significantly elevated in CVDs, especially in heart failure, correlating with NYHA classification and LVEF (%), with higher levels indicating worse cardiac function.</p><p><strong>Conclusions: </strong>The new automatic NT-IGFBP-4 (CLIA) assay offers a highly specific, sensitive and precise method for quantifying IGFBP-4 fragments. Its validated performance and disease association findings would enhance its diagnostic and prognostic potential in CVD research, particularly in heart failure.</p>","PeriodicalId":10390,"journal":{"name":"Clinical chemistry and laboratory medicine","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144945302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexander Lenard, Andreas Rapp, Steffen Busch, Peter Findeisen
{"title":"Method comparison of diabetes mellitus associated autoantibodies in serum specimens.","authors":"Alexander Lenard, Andreas Rapp, Steffen Busch, Peter Findeisen","doi":"10.1515/cclm-2025-0137","DOIUrl":"https://doi.org/10.1515/cclm-2025-0137","url":null,"abstract":"<p><strong>Objectives: </strong>Autoantibodies against structure elements of the pancreas are an essential part of laboratory diagnosis of diabetes mellitus. The heterogeneity of current methods and difficult inter-assay comparability of results poses challenges to both clinical interpretation as well as research integrity.</p><p><strong>Methods: </strong>We conducted a method validation study comparing the measurement of autoantibodies against glutamic acid decarboxylase (GADA), islet antigen 2 (IA-2A), and zinc transporter 8 (ZnT8A) on three commercially available platforms (EUROLabWorkstation analyzer, enzyme-linked immunosorbent assay (ELISA); iFlash 1800 (chemiluminescence immunoassay (CLIA); Maglumi 800 (CLIA)).</p><p><strong>Results: </strong>Compared to the results from EUROLabWorkstation analyzer that was routinely used in our laboratory, the Maglumi demonstrated an acceptable agreement and deviation for GADA (75.4-35.8 %) and IA-2A (71.7-50.3 %). The iFlash displayed less favorable results with agreement and deviation for GADA (51.5-108.8 %) and IA-2A (68-32.5 %). While the iFlash showed excellent agreement for ZnT8A, the Maglumi produced almost exclusively negative results below a 200 U/mL threshold which results in severe underestimation of results on the Maglumi. Overall, no consistent agreement was observed across all three parameters among the CLIA devices tested.</p><p><strong>Conclusions: </strong>Our study reveals significant and clinically relevant discrepancies in the detection of GADA and IA-2A when comparing CLIA devices to the ELISA method routinely used in our laboratory. For individual antibodies up to 65 % of patients who tested positive using ELISA showed negative or borderline results on at least one CLIA device. These deviations are unpredictable and cannot be detected through standard calibration and internal control procedures.</p>","PeriodicalId":10390,"journal":{"name":"Clinical chemistry and laboratory medicine","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144945344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Improvement in the turnaround time of PTH(1-84) as part of the intraoperative PTH monitoring for parathyroidectomy.","authors":"Beverly Buffart, Dragos Barglazan","doi":"10.1515/cclm-2025-0796","DOIUrl":"https://doi.org/10.1515/cclm-2025-0796","url":null,"abstract":"","PeriodicalId":10390,"journal":{"name":"Clinical chemistry and laboratory medicine","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144945367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}