Journal of Applied Laboratory Medicine最新文献

{"title":"Investigating Denosumab Interference in Serum Protein Electrophoresis.","authors":"Sungyu Jee, Jungjun Lee, Hanwool Cho, Hyojin Chae","doi":"10.1093/jalm/jfag135","DOIUrl":"https://doi.org/10.1093/jalm/jfag135","url":null,"abstract":"<p><strong>Background: </strong>Therapeutic monoclonal antibodies, widely used in multiple myeloma (MM), can interfere with the interpretation of serum protein electrophoresis (SPEP) and immunofixation electrophoresis results, challenging the differentiation from endogenous monoclonal (M) proteins associated with the disease. Although this interference has been well established for several therapeutic monoclonal antibodies, the potential impact of denosumab, an IgG2(κ) antibody used to treat MM-related bone disease, remains unclear.</p><p><strong>Methods: </strong>We characterized the electrophoretic migration of denosumab using in vitro spiking experiments. To evaluate in vivo interference, we performed a retrospective review of SPEP and immunotyping results from 110 patients with MM receiving denosumab. Finally, we used matrix-assisted desorption/ionization time-of-flight mass spectrometry (using the EXENT system) to distinguish between denosumab and endogenous M-proteins based on molecular mass.</p><p><strong>Results: </strong>In vitro, denosumab migrated to the mid-to-distal gamma region, nearer the cathodal end than daratumumab, with a normalized migration ratio of approximately 1.34. Among the 110 patients, one exhibited a corresponding IgG(κ) peak on SPEP and immunotyping with the specified migration position, although mass spectrometry confirmed this to be an endogenous M-protein rather than denosumab. No denosumab-specific interference was detected above the lower limit of quantification (15 mg/L) using mass spectrometry.</p><p><strong>Conclusions: </strong>Although denosumab exhibited a consistent electrophoretic migration pattern in vitro, it did not cause clinically relevant in vivo interference in SPEP or immunotyping assays. These findings support accurate electrophoretic interpretation and reduce concerns regarding misclassification of M-proteins in patients with MM receiving denosumab.</p>","PeriodicalId":46361,"journal":{"name":"Journal of Applied Laboratory Medicine","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149138693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiplexed Aptamer-Based Proteomic Data Normalization (Adaptive Normalization by Maximum Likelihood) Significantly Influences Results in Critically Ill Patients.","authors":"Ian B Stanaway, Neha A Sathe, F Linzee Mabrey, Elizabeth Kiernan, Mark M Wurfel, Laura E Evans, Eric D Morrell, Pavan K Bhatraju","doi":"10.1093/jalm/jfag159","DOIUrl":"https://doi.org/10.1093/jalm/jfag159","url":null,"abstract":"<p><strong>Background: </strong>Blood-based proteomics are employed in cohorts of patients with critical illness to provide biologic insights and improve diagnosis and risk stratification. Somalogic developed a multiplex aptamer-based platform (Somascan) with thousands of proteins assayed in a single plasma sample. Results are reported in 2 forms: (a) adaptive normalization by maximum likelihood (ANML), which normalizes measurements to a healthy US population and (b) a non-ANML-normalized form. It is unknown how ANML-normalization influences measurements and associations with outcomes.</p><p><strong>Methods: </strong>We correlated ANML and non-ANML protein quantification with 9 immunoassay biomarkers measured in the same patients' blood samples from the COVID-19 Host Response and Clinical Outcomes (CHROME) cohort. We compared the association of log2 relative fluorescent units (RFUs) with hospital mortality with and without ANML-normalization using adjusted (age, sex, body mass index [BMI]) logistic regression. Results report the odds ratio per doubling of each protein's RFU and declared significance at a false discovery rate (FDR) <0.05.</p><p><strong>Results: </strong>Among 197 patients the average age was 54 years (±16), 51% had COVID-19, 65% were male and hospital mortality was 26%. All biomarkers had equal or higher Pearson correlation between non-ANML-normalization and immunoassay data compared to ANML-normalization. Thousands of proteins changed directionality and significance for risk of mortality based on whether data was ANML-normalized, with 108 of the associations being significant in both, but opposite directionality. The paired Cohen D agreement between beta estimates was moderate (D = 0.61; 95% CI, 0.58-0.64).</p><p><strong>Conclusions: </strong>In this cohort of critically ill patients, ANML-normalization attenuated correlations with immunoassays and largely changed the distribution and direction of significant mortality-associated proteins compared with non-ANML-normalization.</p>","PeriodicalId":46361,"journal":{"name":"Journal of Applied Laboratory Medicine","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149128907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monitoring of Intensive Care Patients by a Physiology-Related GFR Method.","authors":"Bertil Kågedal, Jean-Baptiste Woillard, Stephan Ehrmann, Charlotte Salmon-Gandonnière, Isabelle Benz-de Bretagne, Carl-Fredrik Mandenius","doi":"10.1093/jalm/jfag151","DOIUrl":"https://doi.org/10.1093/jalm/jfag151","url":null,"abstract":"<p><strong>Background: </strong>In the intensive care of critically ill patients, accurate and reliable determination of the glomerular filtration rate (GFR) is of utmost importance. We have previously used one of the most established methods for this purpose, iohexol plasma clearance measurement, in combination with a mechanistic model based on mass balances and physiological intercompartmental transport. Here, we apply this method in an intensive care unit setting to investigate its validity for estimating GFR and to interpret data from critically ill patients.</p><p><strong>Methods: </strong>In 86 patients undergoing advanced supportive care for shock, sepsis, or other severe conditions, GFR was estimated using the clearance of iohexol during 24 h after an intravenous injection. Individual iohexol plasma clearance was determined by the mass balance model. Parameters were fitted to each patient's plasma clearance profiles to estimate GFR. The model estimates were compared with estimations using the established Bröchner-Mortensen regression approach and a maximum a posteriori Bayesian estimator.</p><p><strong>Results: </strong>Iohexol plasma disappearance was stable over the 24-h monitoring period in 80% of patients, while 20% exhibited unstable elimination profiles. In patients with stable profiles, the mechanistic model showed significant correlations with Bröchner-Mortensen estimates and the Bayesian estimator.</p><p><strong>Conclusion: </strong>This physiology-based model strengthens the determination of GFR by providing interpretable parameters linked to transport and exchange processes between plasma and extracellular volumes and urinary excretion. The model shows that short-term GFR changes can be illustrated during the plasma concentration trajectory of iohexol, and short-term GFRs can be calculated.</p>","PeriodicalId":46361,"journal":{"name":"Journal of Applied Laboratory Medicine","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149070434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Impact of Age, Comorbidity, and Current Medication Use on Plasma p-tau217 in Adolescents: A Pilot Study.","authors":"Stephani L Stancil, Mariah E Brewe, Hana Mayfield, Jill Morris","doi":"10.1093/jalm/jfag147","DOIUrl":"10.1093/jalm/jfag147","url":null,"abstract":"<p><strong>Background: </strong>Adolescence is a critical period of neurodevelopment with the emergence of chronic medical conditions and increasing exposure to long-term medications. Phosphorylated tau at threonine 217 (p-tau217) is a sensitive blood-based biomarker of neuropathology in older adults, yet its developmental behavior and susceptibility to common clinical factors in youth are unclear. Here we tested whether p-tau217 varies with age, comorbidity, or medication use during adolescence and whether collection method (venous vs Tasso+ capillary) yields comparable concentrations.</p><p><strong>Methods: </strong>In an adolescent cohort, plasma p-tau217 was measured by Simoa HD-X. Paired venous and Tasso+ capillary samples were also analyzed from adult volunteers for methodological comparison.</p><p><strong>Results: </strong>In adolescents (n = 41; mean age 16 ± 2.6 years), p-tau217 did not correlate with age or body mass index z score and did not differ by psychiatric, cardiometabolic, or gastrointestinal comorbidity nor by corresponding medication use. In contrast, p-tau217 concentrations were >10-fold higher in Tasso+ capillary plasma than venous plasma, a discordance replicated in paired adult samples.</p><p><strong>Conclusion: </strong>There was no clear evidence of associations between plasma p-tau217 and common clinical variables in adolescence, yet plasma p-tau217 is highly sensitive to biospecimen collection method. Venous and Tasso+ capillary plasma should not be directly compared or pooled until methodological differences are resolved. These data provide the first look at the relationship between p-tau217 and clinical factors during adolescence and provide a critical methodological caution for pediatric neuroscience and decentralized biomarker studies.</p>","PeriodicalId":46361,"journal":{"name":"Journal of Applied Laboratory Medicine","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149070421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cardiac Troponin T Stability Study for Regulatory Approval of the 6th Generation High-Sensitivity Assay.","authors":"Nina M Diederiks, Jorik H Amesz, Fred P H T M Romijn, Enrico de Koning, Mark J Boogers, Christa M Cobbaert","doi":"10.1093/jalm/jfag148","DOIUrl":"https://doi.org/10.1093/jalm/jfag148","url":null,"abstract":"<p><strong>Background: </strong>High-sensitivity cardiac troponin T (hs-cTnT) assays must meet strict criteria prior to regulatory approval, as the test is central to myocardial infarction diagnosis. Evaluating analyte stability is essential for ensuring accurate results in stored samples. Here, cTnT stability using the novel sixth-generation assay was evaluated. We also discuss regulatory complexity.</p><p><strong>Methods: </strong>From patients with acute coronary syndrome, serum and lithium heparin plasma (Li-Hep) were collected, pooled per matrix, and aliquoted. One aliquot was immediately analyzed (fresh) while the remainder was stored at ≤-60°C. Selected aliquots were thawed and measured (fresh-frozen) before transfer to 15-25°C for 3 and 5 h, or 2-8°C for 11 and 24 h. Long-term aliquots were transferred frozen to -15 to -25°C for ≥13 months or ≤-60 for 9 and ≥13 months. Measurements were performed in quadruplicate using the Elecsys® hs-cTnT Gen 6 assay on a Cobas® Pure analyzer (Roche Diagnostics). Recovery was calculated relative to fresh measurements. Maximum permissible differences (MPD) were ±1.2 ng/L, ±20%, and ±15% for cTnT concentrations <6 ng/L, ≥6-≤24 ng/L, and >24 ng/L, respectively, allowing one exceedance per condition.</p><p><strong>Results: </strong>In total, >2000 measurements were performed in 18 distinct samples per matrix. Median cTnT concentrations were 49.3 ng/L (8.4-782) in Li-Hep and 49.8 ng/L (8.5-822) in serum. The observed deviation in recovery was below the MPD for all storage conditions and acceptance criteria were met.</p><p><strong>Conclusions: </strong>Stability of cTnT using the sixth-generation hs-cTnT test was demonstrated across different storage conditions for serum and Li-Hep.</p>","PeriodicalId":46361,"journal":{"name":"Journal of Applied Laboratory Medicine","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149065044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Equation Disagreement as a Zero-Cost Uncertainty Signal for LDL-C Classification: An Interpretable Regime-Aware Calibration Model Rescues Misclassification at Treatment Thresholds.","authors":"Ronald Doku, Nana Yaw A Osafo, John Kwagyan, William M Southerland","doi":"10.1093/jalm/jfag139","DOIUrl":"https://doi.org/10.1093/jalm/jfag139","url":null,"abstract":"<p><strong>Background: </strong>Three LDL cholesterol (LDL-C) estimation equations (Friedewald, Sampson/NIH, and Martin-Hopkins) can be calculated from every standard lipid panel, yet laboratories typically report only one. We tested whether disagreement identifies misclassification risk at clinical thresholds and whether simple calibration improves accuracy in this subgroup.</p><p><strong>Methods: </strong>We analyzed 10 799 All of Us lipid panels using direct LDL-C as the reference standard. At 70, 100, and 130 mg/dL [1.81, 2.59, and 3.36 mmol/L], panels were classified as Agree if all 3 equations fell on the same side and Disagree otherwise. A regime-aware calibration model was compared with 7 machine learning (ML) methods using 5-fold cross-validation and tested in 14 549 hospital-based Medical Information Mart for Intensive Care IV panels.</p><p><strong>Results: </strong>When equations agreed (86%-92% of panels), accuracy was 92% to 96%; when they disagreed (8%-14%), accuracy fell to 48%-61%. The model's mean absolute error was 8.98 mg/dL (0.232 mmol/L), matching the best ML ensemble (9.01 mg/dL [0.233 mmol/L]; 95% CI for the difference, -0.35 to 0.29 mg/dL [-0.009 to 0.008 mmol/L]). In external validation, among split-threshold panels, the model outperformed the best-performing individual equation at each threshold by 3.5 to 9.0 percentage points and the majority vote by 18.5 to 25.2 percentage points. Calibration improved accuracy by 19 to 25 percentage points; hybrid routing achieved 90%-93% accuracy internally and 90%-94% externally.</p><p><strong>Conclusions: </strong>Equation disagreement is a zero-cost uncertainty signal identifying patients at highest misclassification risk. A simple, interpretable calibration model improves classification while matching the best-performing ML ensemble.</p>","PeriodicalId":46361,"journal":{"name":"Journal of Applied Laboratory Medicine","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149065050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analytical Verification of a Point-of-Care High-Sensitivity Troponin I Assay.","authors":"John W Pickering, Vanessa Buchan, Megan Rodney, Tamsin Attenburrow, Laura R Joyce, Martin Than, Christopher M Florkowski","doi":"10.1093/jalm/jfag143","DOIUrl":"https://doi.org/10.1093/jalm/jfag143","url":null,"abstract":"<p><strong>Background: </strong>To provide independent evidence of the analytical performance of the i-STAT high-sensitivity troponin I assay using the i-STAT Alinity system, we assessed imprecision, hemolysis interference, and concordance with laboratory assays.</p><p><strong>Methods: </strong>Nine whole-blood samples with concentrations from below the limit of quantitation to approximately 10 times the upper reference limit were analyzed 20 times in succession. Four samples across a similar range were used to assess hemolysis interference induced by repeated aspiration through a 25-gauge needle. Concordance with 4 laboratory comparison assays was assessed with 200 samples by Pearson correlation and κ statistics at the upper reference limit (URL) and compared to concordance between the laboratory assays.</p><p><strong>Results: </strong>CVs were <10% across the range of 10 to 20 ng/L, below the universal URL. There were small changes with hemolysis but within acceptable limits (±3 ng/L below 10 ng/L and ±30% above 10 ng/L). Correlation coefficients with high-sensitivity troponin I laboratory assays ranged from 0.96 to 0.99, and performance across the URL ranged from a κ of 0.67 to 0.89, similar to results between laboratory assays (correlation range, 0.87-0.98; κ at the URL range, 0.71-0.88).</p><p><strong>Conclusions: </strong>Imprecision met manufacturer claims and was consistent with a high-sensitivity assay. There was no significant hemolysis interference. Concordance with comparison laboratory assays was similar to that between laboratory assays. The results support performance characteristics previously reported by the manufacturer, and the assay and analyzer offer acceptable performance for intended clinical use.</p><p><strong>Australian new zealand clinical trials registry number: </strong>ACTRN12625000710426.</p>","PeriodicalId":46361,"journal":{"name":"Journal of Applied Laboratory Medicine","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149018218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of an Upper Arm Capillary Blood Collection Device Compared with Venous and Fingerstick Sampling.","authors":"Stacy G Beal, Anissa Naranjo, Carlos Torres, Claire Carter, Joyce Chen, Michael Rummel, Jenny Trau, Breland Hockman","doi":"10.1093/jalm/jfag145","DOIUrl":"https://doi.org/10.1093/jalm/jfag145","url":null,"abstract":"<p><strong>Background: </strong>Upper arm capillary blood collection devices may expand access to laboratory testing outside traditional phlebotomy settings. We evaluated the analytical performance and patient preference of the ImPress, an investigational-use upper arm capillary blood collection device compared with venous and fingerstick sampling.</p><p><strong>Methods: </strong>Matched samples were collected from 43 healthy volunteers. Sixteen routine chemistry and lipid analytes were measured on standard laboratory platforms. Agreement was assessed using Deming regression and bias at medical decision points (MDPs), with acceptability defined by total allowable error (TEa). Hemolysis indices were compared across collection methods. Participants completed a survey.</p><p><strong>Results: </strong>A total of 315 specimens were analyzed. Thirteen of 16 analytes met predefined acceptance criteria for upper arm capillary compared with venous sampling. Mean bias at MDP ranged from -3.1% to 10% for venous vs upper arm capillary samples. Albumin, calcium, and aspartate aminotransferase (AST) did not meet acceptance criteria, primarily because all samples were within a tight normal range. All correlation coefficients (R, Deming regression) were ≥0.90, indicating linear relationships between collection modalities. Hemolysis indices for samples collected by the upper arm capillary device were well below assay interference thresholds. Mean pain scores (0 to 10 scale) were lowest for upper arm capillary (0.55) compared with venipuncture (2.61) and fingerstick (2.87). Most participants (74%) reported a preference for an upper arm capillary device.</p><p><strong>Conclusions: </strong>Upper arm capillary blood collection demonstrated strong analytical agreement with venous and fingerstick sampling for most routine analytes, low clinically significant hemolysis, and high patient acceptability. These findings support its potential use in decentralized and remote laboratory testing.</p>","PeriodicalId":46361,"journal":{"name":"Journal of Applied Laboratory Medicine","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149018206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Blood Glucose Measurement Methods at Low Concentrations in Neonates at Risk for Hypoglycemia.","authors":"Alyssa Lee, Liyun Cao","doi":"10.1093/jalm/jfag144","DOIUrl":"https://doi.org/10.1093/jalm/jfag144","url":null,"abstract":"<p><strong>Background: </strong>Accurate assessment of low-level blood glucose is essential for managing neonatal hypoglycemia. This study compared low-level neonatal glucose measurements across commonly used platforms and evaluated the potential clinical implications of method-specific differences.</p><p><strong>Methods: </strong>Paired neonatal glucose were measured using the Accu-Chek Inform II blood glucose monitoring system (BGMS) device and the Radiometer ABL90 Flex Plus blood gas analyzer. A subset of paired samples was also compared with the Beckman Coulter AU5800 hexokinase method. Method agreement was assessed using Deming regression and Bland-Altman analysis. Exploratory analyses evaluated impact of clinical characteristics, including gestational age, birth weight, growth status, and delivery mode.</p><p><strong>Results: </strong>Agreement between Accu-Chek and ABL90 was modest (R = 0.558) with wide limits of agreement (-13.21 to 12.95 mg/dL; -0.73 to 0.72 mmol/L) and a bidirectional bias pattern. Positive-bias samples showed a mean bias of 6.13 mg/dL (0.34 mmol/L), whereas negative-bias samples showed -5.29 mg/dL (-0.29 mmol/L). By contrast, Accu-Chek demonstrated strong agreement with the AU5800 hexokinase method (R = 0.976) and narrower limits of agreement (-2.53 to 6.64 mg/dL; -0.14 to 0.37 mmol/L). No significant associations were identified between absolute bias and neonatal clinical characteristics.</p><p><strong>Conclusions: </strong>At low glucose concentrations, agreement between the Accu-Chek and ABL90 was variable and bidirectional, while agreement between the BGMS meter and the hexokinase method was strong. The lack of association between analytical bias and neonatal characteristics suggests that platform-specific analytical performance, rather than patient factors, accounts for variability at clinically relevant glucose levels.</p>","PeriodicalId":46361,"journal":{"name":"Journal of Applied Laboratory Medicine","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149012984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Half-Life of Long Forms of Cardiac Troponin T.","authors":"Rasmus Bo Hasselbalch, Selma Salonen, Jonas Henrik Kristensen, Tuulia Tuominen, Nina Strandkjær, Morten Østergaard, Hasse Møller-Sørensen, Jens Christian Nilsson, Morten Dahl, Mustafa Vakur Bor, Ruth Frikke-Schmidt, Niklas Rye Jørgensen, Line Rode, Lene Holmvang, Jesper Kjærgaard, Lia E Bang, Julie Forman, Kim P Dalhoff, Allan S Jaffe, Kristian Thygesen, Henning Bundgaard, Saara Wittfooth, Kasper Karmark Iversen","doi":"10.1093/jalm/jfag142","DOIUrl":"https://doi.org/10.1093/jalm/jfag142","url":null,"abstract":"<p><strong>Background: </strong>Long forms of cardiac troponin T (cTnT) are promising markers that may differentiate myocardial infarction from other causes of acute and chronic myocardial injury. However, to understand the clinical utility of long cTnT, knowledge of the half-life (T½) is key. By using auto-transfusion in humans we determined the T½ of long forms of cTnT and compared long cTnT to a commercial high-sensitivity total cTnT assay.</p><p><strong>Methods: </strong>Patients with ST-segment-elevation-myocardial infarction were included within 24 h after revascularization and underwent plasmapheresis to obtain plasma with a high cTnT concentration. After at least 3 weeks, patients returned for an autologous plasma re-transfusion followed by repeated blood sampling. A novel assay measured long cTnT and a commercially available assay measured total cTnT.</p><p><strong>Results: </strong>We included 17 patients with median age 63 years (25th-75th percentiles 59-70), and 4 (24%) were female. The median concentrations after transfusion were 99 ng/L (54-125) for long cTnT vs 252 ng/L (233-322) for total cTnT. The median ratio of long cTnT to total cTnT was 0.39 (0.26-0.55) after transfusion and declined to 0.30 (0.20-0.44) after 60 min. Long cTnT displayed a 2-phase exponential decay, similar to what was observed for total cTnT but with shorter T½ both for the distribution phase [16 min (11-18) vs 22 min (20-24), P < 0.001] and the elimination phase [103 min (78-125) vs 133 min (114-168), P < 0.001].</p><p><strong>Conclusion: </strong>The elimination of long forms of cTnT was faster than for total cTnT following re-transfusion. This understanding could aid in differentiating myocardial infarction from other causes of acute and chronic myocardial injury.</p>","PeriodicalId":46361,"journal":{"name":"Journal of Applied Laboratory Medicine","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148991908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}