Evaluation of a New Skeletal Troponin I Assay in Patients with Idiopathic Inflammatory Myopathies

2020 ◽  
Vol 5 (2) ◽  
pp. 320-331
Author(s):  
Katriina Bamberg ◽  
Laura Mehtälä ◽  
Olli Arola ◽  
Seppo Laitinen ◽  
Pauliina Nordling ◽  
...  

Abstract Background The current biomarkers for diagnosis and monitoring of injured and diseased skeletal muscles, such as creatine kinase (CK), have limited tissue specificity and incapability to differentiate between pathological and physiological changes. Thus, new biomarkers with improved diagnostic accuracy are needed. Our aim was to develop and validate a novel assay for skeletal troponin I (skTnI), and to assess its clinical performance in patients with idiopathic inflammatory myopathies (IIM). Methods A two-step fluoroimmunoassay was used to analyze samples from healthy reference individuals (n = 140), patients with trauma (n = 151), and patients with IIM (n = 61). Results The limit of detection was 1.2 ng/mL, and the upper reference limit (90th percentile) was 5.2 ng/mL. The median skTnI concentrations were <limit of detection (LoD), 2.7 ng/mL, and 8.6 ng/mL in reference, trauma, and IIM cohorts, respectively. Differences in measured skTnI levels were statistically significant between all three study cohorts (Kruskal–Wallis P < 0.001; Mann–Whitney P < 0.001 for all). skTnI and CK had a strong positive correlation (Spearman’s r = 0.771, P < 0.001), and the longitudinal changes in skTnI mirrored those observed with CK. Conclusions With the skTnI assay, patients with IIM were identified from healthy individuals and from patients with traumatic muscular injuries. When compared to CK, skTnI appeared to be more accurate in managing patients with low-grade IIM disease activities. The developed assay serves as a reliable analytical tool for the assessment of diagnostic accuracy of skTnI in the diagnosis and monitoring of myopathies.

Author(s):  
Giuseppe Lippi ◽  
Anna Ferrari ◽  
Giorgio Gandini ◽  
Matteo Gelati ◽  
Claudia Lo Cascio ◽  
...  

AbstractBackground:This study was aimed to evaluate the analytical performance of the novel chemiluminescent and fully-automated Beckman Coulter Access hsTnI high-sensitivity immunoassay for measurement of cardiac troponin I (cTnI).Methods:The study, using lithium heparin samples, included assessment of limit of blank (LOB), limit of detection (LOD), functional sensitivity, linearity, imprecision (within run, between-run and total), calculation of 99th percentile upper reference limit (URL) in 175 healthy blood donors (mean age, 36±12 years; 47% women) and comparison with two other commercial cTnI immunoassays.Results:The LOB, LOD and functional sensitivity of Access hsTnI were 0.14, 0.34 and 1.35 ng/L, respectively. The within-run, between-run and total imprecision was 2.2%–2.9%, 4.6%–5.4%, and 5.4%–6.1%, respectively. The linearity was excellent in the range of cTnI values between 0.95 and 4195 ng/L (r=1.00). The 99th percentile URL was 15.8 ng/L. Measurable cTnI values were found in 173/175 healthy subjects (98.9%). Good agreement of cTnI values was found with AccuTnI+3 (r=0.97; mean bias, −9.3%), whereas less satisfactory agreement was found with Siemens Dimension Vista cTnI (r=0.95; mean bias, −55%).Conclusions:The results of our evaluation of the Beckman Coulter Access hsTnI indicate that the analytical performance of this fully-automated immunoassay is excellent.


2019 ◽  
Vol 58 (1) ◽  
pp. 138-145 ◽  
Author(s):  
Federica Braga ◽  
Elena Aloisio ◽  
Andrea Panzeri ◽  
Takahito Nakagawa ◽  
Mauro Panteghini

Abstract Background Highly sensitive cardiac troponin assays (hs-cTn) are not available as point-of-care (POC) measurements. As rapid testing cannot be achieved at the expense of clinical performance, there is an urgent need to develop and rigorously validate POC hs-cTn. Konica Minolta (KM) has recently developed a surface plasmon-field enhanced fluorescence spectroscopy-based POC hs-cTn I system. Methods We validated the analytical characteristics of the KM POC system according to the international guidelines. Results Limit of blank (LoB) and limit of detection (LoD) were 0.35 and 0.62 ng/L, respectively, hs-cTn I concentrations corresponding to a total CV of 20%, 10% and 5% were 1.5, 3.9 and 11.0 ng/L, respectively. Method comparison studies showed that KM calibration was successfully traced to higher-order references. Limit of quantitation (LoQ), i.e. the hs-cTn I concentration having a total error of measurement of ≤34%, was 10.0 ng/L. The upper reference limit (URL) for 600 healthy blood donors was calculated at 12.2 ng/L (90% confidence interval [CI]: 9.2–39.2), while sex-partitioned URLs were 20.6 (males) and 10.7 ng/L (females), respectively (p < 0.0001). KM assay measured hs-cTn I concentrations >LoD in 65.7% of all reference individuals, in 76.7% of males and in 54.7% of females, respectively. Conclusions The KM system joins the characteristics of POC systems to the analytical performance of hs-cTn.


Author(s):  
Peter A. Kavsak ◽  
Tara Edge ◽  
Chantele Roy ◽  
Paul Malinowski ◽  
Karen Bamford ◽  
...  

AbstractObjectivesTo analytically evaluate Ortho Clinical Diagnostics VITROS high-sensitivity cardiac troponin I (hs-cTnI) assay in specific matrices with comparison to other hs-cTn assays.MethodsThe limit of detection (LoD), imprecision, interference and stability testing for both serum and lithium heparin (Li-Hep) plasma for the VITROS hs-cTnI assay was determined. We performed Passing-Bablok regression analyses between sample types for the VITROS hs-cTnI assay and compared them to the Abbott ARCHITECT, Beckman Access and the Siemens ADVIA Centaur hs-cTnI assays. We also performed Receiver-operating characteristic curve analyses with the area under the curve (AUC) determined in an emergency department (ED)-study population (n=131) for myocardial infarction (MI).ResultsThe VITROS hs-cTnI LoD was 0.73 ng/L (serum) and 1.4 ng/L (Li-Hep). Stability up to five freeze-thaws was observed for the Ortho hs-cTnI assay, with the analyte stability at room temperature in serum superior to Li-Hep with gross hemolysis also affecting Li-Hep plasma hs-cTnI results. Comparison of Li-Hep to serum concentrations (n=202), yielded proportionally lower concentrations in plasma with the VITROS hs-cTnI assay (slope=0.85; 95% confidence interval [CI]:0.83–0.88). In serum, the VITROS hs-cTnI concentrations were proportionally lower compared to other hs-cTnI assays, with similar slopes observed between assays in samples frozen <−70 °C for 17 years (ED-study) or in 2020. In the ED-study, the VITROS hs-cTnI assay had an AUC of 0.974 (95%CI:0.929–0.994) for MI, similar to the AUCs of other hs-cTn assays.ConclusionsLack of standardization of hs-cTnI assays across manufacturers is evident. The VITROS hs-cTnI assay yields lower concentrations compared to other hs-cTnI assays. Important differences exist between Li-Hep plasma and serum, with evidence of stability and excellent clinical performance comparable to other hs-cTn assays.


1986 ◽  
Vol 32 (1) ◽  
pp. 186-191 ◽  
Author(s):  
T R Koch ◽  
U J Mehta ◽  
H C Nipper

Abstract We studied the analytical and clinical performance of six methods for creatine kinase (EC 2.7.3.2) isoenzyme MB (CK-MB): three immunoassays (Behring, Hybritech, and International Immunoassay Labs); one immunoinhibition assay (Roche); one immunoinhibition/column method (Du Pont); and one electrophoretic method (Beckman). Between-day precision for all kits was poor at the upper reference limit. All methods gave results linearly related to CK-MB concentration and all were free from CK-MM, CK-BB, and adenylate kinase interference. Only the Du Pont method was adversely affected by atypical isoenzymes. For diagnosis of acute myocardial infarction in a coronary care population (n = 40; prevalence = 45%), all methods were approximately 95% efficient, when appropriate reference criteria were used. Some manufacturers fail to provide data for an appropriate (acutely ill, non-infarct) reference population; decreased diagnostic specificity may result from use of reference ranges based on results for healthy subjects. Expression of CK-MB as a percent of total CK degrades efficiency unless total CK is markedly increased.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Michael Briscoe ◽  
Robert A Sykes ◽  
Thomas Krysztofiak ◽  
Kenneth Mangion ◽  
Oliver H Peck ◽  
...  

Introduction: Unplanned hospitalizations are commonly associated with a circulating troponin concentration >99 th percentile upper reference limit (URL). In order to better understand the clinical significance of troponin elevation, we evaluated outcomes in hospitalized patients according to cardiac endotype. Methods: We prospectively screened consecutive hospitalized patients with elevated high-sensitivity troponin-I (hs-TnI) concentrations (Abbott ARCHITECT troponin-I assay; sex-specific URL, 99 th centile: male: >34ng/L; female: >16ng/L) within a regional cardiac care network (population 650,000). A cardiology clinical team adjudicated individual patient records and assigned endotypes by consensus agreement according to the Fourth Universal Definition of Myocardial Infarction (MI). Endotypes were sub-classified into etiological category by inciting event(s). Characteristics and comorbidity were compared and outcomes recorded on virtual follow-up until June 2 nd 2020. Results: A total of 390 consecutive patients with ≥1 hs-TnI value >URL between March 1-April 15, 2020, were evaluated; 44 patients were excluded ( Duplicates: 2; Missing data: 41; Research patient: 1 ). Of 346 who qualified for inclusion, an index diagnosis of Type 1 MI (T1MI), T2MI and myocardial injury were assigned in 115 (33.2%), 79 (22.8%) and 152 (43.9%) patients, respectively. Compared with T1MI, patients with T2MI and myocardial injury had lower peak hs-TnI values (median [IQR]: 86 [250-697] vs 5020 [853-7774]ng/L; p< 0.01), lower estimated 10-year survival (40.2% vs 53.4%; p=0.002), less frequently underwent coronary revascularization (1.4% vs 45.2%; p<0.0005) and had longer inpatient stay (13.0 vs 6.1 days). Inpatient and overall mortality rates from admission to follow-up (median [range]: 71 [0-151] days) were higher among patients with T2MI and myocardial injury (19.9% vs 7.8%; p=0.004; and 26.0% vs 11.3%; Log rank (Mantel-Cox) X 2 = 1.927; p=0.003) independent of similar cardiovascular risk profiles. Conclusions: Despite lower peak circulating troponin concentrations, patients with T2MI and myocardial injury had higher inpatient mortality, lower estimated 10-year survival and longer in-hospital stay compared to those with T1MI.


2019 ◽  
Vol 65 (11) ◽  
pp. 1426-1436 ◽  
Author(s):  
Jasper Boeddinghaus ◽  
Raphael Twerenbold ◽  
Thomas Nestelberger ◽  
Luca Koechlin ◽  
Desiree Wussler ◽  
...  

Abstract BACKGROUND We aimed to validate the clinical performance of the high-sensitivity cardiac troponin I [VITROS® Immunodiagnostic Products hs Troponin I (hs-cTnI-VITROS)] assay. METHODS We enrolled patients presenting to the emergency department with symptoms suggestive of acute myocardial infarction (AMI). Final diagnoses were centrally adjudicated by 2 independent cardiologists considering all clinical information, including cardiac imaging: first, using serial hs-cTnT-Elecsys (primary analysis) and, second, using hs-cTnI-Architect (secondary analysis) measurements in addition to the clinically used (hs)-cTn. hs-cTnI-VITROS was measured at presentation and at 1 h in a blinded fashion. The primary objective was direct comparison of diagnostic accuracy as quantified by the area under the ROC curve (AUC) of hs-cTnI-VITROS vs hs-cTnT-Elecsys and hs-cTnI-Architect, and in a subgroup also hs-cTnI-Centaur and hs-cTnI-Access. Secondary objectives included the derivation and validation of an hs-cTnI-VITROS-0/1-h algorithm. RESULTS AMI was the adjudicated final diagnosis in 158 of 1231 (13%) patients. At presentation, the AUC for hs-cTnI-VITROS was 0.95 (95% CI, 0.93–0.96); for hs-cTnT-Elecsys, 0.94 (95% CI, 0.92–0.95); and for hs-cTnI-Architect, 0.92 (95% CI, 0.90–0.94). AUCs for hs-cTnI-Centaur and hs-cTnI-Access were 0.95 (95% CI, 0.94–0.97). Applying the derived hs-cTnI-VITROS-0/1-h algorithm (derivation cohort n = 519) to the validation cohort (n = 520), 53% of patients were ruled out [sensitivity, 100% (95% CI, 94.1–100)] and 14% of patients were ruled in [specificity, 95.6% (95% CI, 93.4–97.2)]. Patients ruled out by the 0/1-h algorithm had a survival rate of 99.8% at 30 days. Findings were confirmed in the secondary analyses using the adjudication including serial measurements of hs-cTnI-Architect. CONCLUSIONS The hs-cTnI-VITROS assay has at least comparable diagnostic accuracy with the currently best validated hs-cTnT and hs-cTnI assays. ClinicalTrials.gov Identifier NCT00470587.


Author(s):  
Pascale Beyne ◽  
Erik Bouvier ◽  
Patrick Werner ◽  
Pierre Bourgoin ◽  
Damien Logeart ◽  
...  

AbstractThe aim of this study was to define the use of a new cardiac troponin I (cTnI) assay for emergency patients with chest pain and no specific electrocardiographic changes consistent with the presence of ischemia. Patients (n=106) admitted in Emergency/Cardiology Departments for chest pain and suspicion of acute coronary syndrome (ACS) were randomized into two diagnosis groups (ACS or non-ACS) by two independent cardiologists. cTnI measurements were performed at admission, and 6 hours and 12 hours later with a new generation assay (Access AccuTnI, Beckman Coulter). Using an upper reference limit of 0.04 μg/l, 27 patients had a cTnI elevation not related to the final diagnosis of ischemia; the positive predictive value (PPV) was 67% with specificity 48%. The decisional value was re-defined and set at 0.16 μg/l, a concentration corresponding to the 99th percentile of the non-ACS patient group. Precision (coefficient of variation) was 8% at this level, PPV 97% and specificity 98%. This new decisional value is now used in our institution and could be included in standard care guidelines to improve the management of patients presenting chest pain in emergency departments.


1997 ◽  
Vol 43 (11) ◽  
pp. 2047-2051 ◽  
Author(s):  
Fred S Apple ◽  
Alireza Falahati ◽  
Pamela R Paulsen ◽  
Elizabeth A Miller ◽  
Scott W Sharkey

Abstract This study compared the diagnostic accuracy of the measurement of serum cardiac troponin I (cTnI) with creatine kinase (CK) MB mass in patients with minor myocardial injury whose measured total CK activity did not exceed twice the upper reference limit (300 U/L for men; 200 U/L for women). Forty-eight consecutive patients presenting with chest pain and with in-hospital documentation of myocardial injury were enrolled. Electrocardiogram, echocardiogram, and serial serum CK-MB mass, cTnI, and total CK were measured over 36 h after admission. Peak total CK activity was within normal limits in 28 patients (58%). The mean (±SD) peak CK-MB mass and cTnI concentrations were: 16.4 (11.8) μg/L and 132 (13.0) μg/L; respectively. The peak biochemical marker index (defined as CK-MB or cTnI divided by its respective upper reference limit) was significantly (P &lt;0.05) higher for cTnI than for CK-MB from 7 to 36 h. The clinical sensitivity for detection of myocardial injury for cTnI was 100% [95% confidence interval (CI): 87.2% to 100%], compared with 81.8% (CI: 67.3% to 91.8%) for CK-MB. Thus, cTnI was more sensitive than CK-MB mass for detection of myocardial injury in patients with small increases of total CK.


2009 ◽  
Vol 36 (12) ◽  
pp. 2711-2714 ◽  
Author(s):  
ROHIT AGGARWAL ◽  
DOROTA LEBIEDZ-ODROBINA ◽  
ALPANA SINHA ◽  
AUGUSTINE MANADAN ◽  
JOHN P. CASE

Objective.To study the association of serum cardiac troponin T (cTnT) and cardiac troponin I (cTnI) with creatine kinase (CK) in patients with idiopathic inflammatory myopathies (IIM).Methods.We performed a retrospective study on patients with IIM followed by the rheumatology service of a county hospital from 2004 to 2008. Patients with myocardial ischemia and/or with renal failure were excluded. Clinical data including electromyogram, muscle biopsy, and CK, cTnT and cTnI were recorded. Patients who had simultaneous analysis of CK and cardiac troponin (cTnT or cTnI) levels were studied. CK levels were correlated with cTnT and cTnI by chi-square test and Spearman correlation.Results.We identified 49 patients with IIM (69 observations) who satisfied our inclusion criteria. The primary diagnosis was polymyositis in 23, dermatomyositis in 16, and myositis associated with connective tissue disease in 10 patients. There were 33/49 women with average age 45.8 years. Twenty-eight patients with IIM had simultaneous CK and cTnT values assayed. Of those patients, 18/23 with elevated CK also had elevated cTnT, and 5/5 patients with normal CK levels had normal cTnT levels (p = 0.005). In 41 patients with IIM who had simultaneous CK and cTnI levels assayed, only 1/29 with elevated CK had elevated cTnI, and 12/12 patients with normal CK had normal cTnI (p = 0.5). CK correlated strongly with the cTnT (r = 0.62, p = 0.001) but did not correlate with cTnI.Conclusion.Elevated cTnT, but not cTnI, was highly associated with CK in patients with IIM despite the absence of myocardial ischemia.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Victor J. van den Berg ◽  
Rohit M. Oemrawsingh ◽  
Victor A. W. M. Umans ◽  
Isabella Kardys ◽  
Folkert W. Asselbergs ◽  
...  

Background Detailed insights in temporal evolution of high‐sensitivity cardiac troponin following acute coronary syndrome (ACS) are currently missing. We aimed to describe and compare the post‐ACS kinetics of high‐sensitivity cardiac troponin I (hs‐cTnI) and high‐sensitivity cardiac troponin T (hs‐cTnT), and to determine their intra‐ and interindividual variation in clinically stable patients. Methods and Results We determined hs‐cTnI (Abbott) and hs‐cTnT (Roche) in 1507 repeated blood samples, derived from 191 patients with ACS (median, 8/patient) who remained free from adverse cardiac events during 1‐year follow‐up. Post‐ACS kinetics were studied by linear mixed‐effect models. Using the samples collected in the 6‐ to 12‐month post‐ACS time frame, patients were then considered to have chronic coronary syndrome. We determined (differences between) the average hs‐cTnI and average hs‐cTnT concentration, and the intra‐ and interindividual variation for both biomarkers. Compared with hs‐cTnT, hs‐cTnI peaked higher (median 3506 ng/L versus 494 ng/L; P <0.001) and was quicker below the biomarker‐specific upper reference limit (16 versus 19 days; P <0.001). In the post–6‐month samples, hs‐cTnI and hs‐cTnT showed modest correlation ( r spearman =0.60), whereas the average hs‐cTnT concentration was 5 times more likely to be above the upper reference limit than hs‐cTnI. The intraindividual variations of hs‐cTnI and hs‐cTnT were 14.0% and 18.1%, while the interindividual variations were 94.1% and 75.9%. Conclusions Hs‐cTnI peaked higher after ACS and was quicker below the upper reference limit. In the post–6‐month samples, hs‐cTnI and hs‐cTnT were clearly not interchangeable, and average hs‐cTnT concentrations were much more often above the upper reference limit than hs‐cTnI. For both markers, the within‐patient variation fell largely below beween‐patient variation. Registration URL: https://www.trialregister.nl ; unique identifiers: NTR1698 and NTR1106.


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