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1.
Clin Chem Lab Med ; 59(4): 749-755, 2021 03 26.
Article in English | MEDLINE | ID: mdl-33079697

ABSTRACT

OBJECTIVES: To analytically evaluate Ortho Clinical Diagnostics VITROS high-sensitivity cardiac troponin I (hs-cTnI) assay in specific matrices with comparison to other hs-cTn assays. METHODS: The 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). RESULTS: The 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. CONCLUSIONS: Lack 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.


Subject(s)
Biological Assay , Myocardial Infarction , Troponin I , Heparin , Humans , Limit of Detection , Myocardial Infarction/diagnosis , ROC Curve
3.
Clin Biochem ; 69: 52-56, 2019 Jul.
Article in English | MEDLINE | ID: mdl-31063741

ABSTRACT

BACKGROUND: Siemens Healthcare Diagnostics has four commercially available assays on different analytical platforms using different methodologies to generate signal. We assessed the analytical performance of the Dimension EXL hs-cTnI assay (LOCI method) across different matrices and compared it to two different acridinium ester-based hs-cTnI assays (ADVIA Centaur and Abbott ARCHITECT). METHODS: The analytical sensitivity and precision below the 99th-percentile was determined for the Dimension EXL hs-cTnI assay. Method comparisons were performed between the Dimension EXL contemporary cTnI and the hs-cTnI assays, between different matrices for the EXL hs-cTnI assay (serum, lithium heparin and EDTA plasma), and between different hs-cTnI assays (EXL versus ADVIA Centaur or Abbott ARCHITECT) using non-parametric analyses. RESULTS: The limit of blank and detection were 0.9 ng/L and 1.7 ng/L, respectively, with imprecision of 5.8% at 8.6 ng/L and 3.2% at 47.5 ng/L. Comparison between the EXL contemporary cTnI and hs-cTnI assay (range: 2.6-4214 ng/L) yielded proportional lower concentrations for the hs-cTnI assay (slope = 0.86; 95%CI: 0.81 to 0.96, n = 40); however, there was no difference in concentrations below 100 ng/L between the assays (median difference = -2.7 ng/L; 95%CI: -9.8 to 9.3). Passing-Bablok regression analysis with EDTA plasma yielded proportionally higher concentrations with the EXL hs-cTnI versus Abbott hs-cTnI (slope = 1.45; 95%CI: 1.02-1.86, n = 40) with proportionally lower concentrations with EDTA versus lithium heparin plasma with the EXL hs-cTnI assay alone (slope = 0.93; 95%CI: 0.90 to 0.99, n = 40). Comparison with Abbott hs-cTnI concentrations below 100 ng/L in the three matrices, indicated that the EXL hs-cTnI assay yielded higher concentrations (median difference range: 3.4-9.4 ng/L), with differences also evident when comparing the EXL hs-cTnI assay to the ADVIA Centaur hs-cTnI assay. CONCLUSION: The Siemens EXL hs-cTnI assay meets the analytical criteria for a high-sensitivity assay, with assay specific cutoffs important to maximize clinical performance.


Subject(s)
Troponin I/blood , Diagnostic Tests, Routine , Female , Humans , Limit of Detection , Male , Middle Aged
4.
Clin Chem Lab Med ; 57(5): 745-751, 2019 04 24.
Article in English | MEDLINE | ID: mdl-30838842

ABSTRACT

Background Manufacturers of high-sensitivity cardiac troponin (hs-cTn) assays have restricted use of what sample types or matrices are acceptable to use for measurement. Our goal was to evaluate the comparability of the Siemens ADVIA Centaur hs-cTnI assay across different matrices and under different storage conditions. Methods Three different QC-plasma matrices were evaluated for imprecision <10 ng/L. Passing-Bablok regression and difference plots were determined for cTnI concentrations spanning the reference interval (limit of quantification to male 99th-percentile: 2.5 ng/L to <60 ng/L) between serum and lithium heparin plasma, lithium heparin and EDTA plasma and between the Siemens and Abbott hs-cTnI assays. Stability at room temperature (RT) and 2-8 °C was also assessed across the three matrices. Results Over 16-weeks the SDs were ≤1.0 ng/L for QCs ranging from 5.0 to 8.3 ng/L. Across the reference interval there was excellent agreement between lithium heparin plasma and serum for the Siemens hs-cTnI assay (slope=0.98/intercept=-0.1), however, cTnI concentrations were proportionally lower in EDTA as compared to lithium heparin plasma (slope=0.90, 95% CI: 0.88-0.92). In lithium heparin plasma the Siemens hs-cTnI concentrations were higher than the Abbott hs-cTnI concentrations (slope=1.26/intercept=-0.2). Stability of cTnI in lithium heparin plasma as compared in serum and EDTA plasma appeared more labile, with decreases ≥20% in concentrations evident as early as 1-day in storage at RT. Conclusions There is excellent agreement in concentrations between lithium heparin plasma and serum with the Siemens ADVIA Centaur hs-cTnI assay; however, cTnI concentrations in EDTA plasma are lower. Reference intervals and clinical studies in EDTA plasma for the Centaur hs-cTnI assay are required before clinical use.


Subject(s)
Troponin I/blood , Blood Chemical Analysis/standards , Blood Specimen Collection , Edetic Acid/chemistry , Heparin/chemistry , Humans , Immunoassay/standards , Quality Control , Reference Values
6.
Clin Chem Lab Med ; 56(7): 1176-1181, 2018 06 27.
Article in English | MEDLINE | ID: mdl-29533903

ABSTRACT

BACKGROUND: Analytical evaluation of high-sensitivity cardiac troponin (hs-cTn) assays, with particular attention to imprecision, interferences and matrix effects, at normal cTn concentrations, is of utmost importance as many different clinical algorithms use concentration cutoffs <10 ng/L for decision-making. The objective for the present analytical study was to compare the new Beckman Coulter hs-cTnI assay (Access hsTnI) to Abbott's hs-cTnI assay in different matrices and for different interferences, with a focus on concentrations <10 ng/L. METHODS: The limit of blank (LoB) and the limit of detection (LoD) were determined in different matrices for the Beckman hs-cTnI assay. Passing-Bablok regression and difference plots were determined for 200 matched lithium heparin and EDTA plasma samples for the Beckman assay and 200 lithium heparin samples for the Abbott assay. Both EDTA and heparin plasma samples were also evaluated for stability under refrigerated conditions, for endogenous alkaline phosphatase interference and for hemolysis and icterus. RESULTS: The Beckman hs-cTnI assay LoB was 0.5 ng/L with the following range of LoDs=0.8-1.2 ng/L, with EDTA plasma yielding lower concentrations as compared to lithium heparin plasma (mean difference=-14.9%; 95% CI=-16.9 to 12.9). Below 10 ng/L, lithium heparin cTnI results from the Beckman assay were on average 1.1 ng/L (95% CI=0.7 to 1.5) higher than the Abbott results, with no difference between the methods when using EDTA plasma (mean difference =-0.1 ng/L; 95% CI=-0.3 to 0.2). Low cTnI concentrations were less effected by interferences in EDTA plasma. CONCLUSIONS: The Access hsTnI method can reliably detect normal cTnI concentrations with both lithium heparin and EDTA plasma being suitable matrices.


Subject(s)
Biological Assay/methods , Troponin I/blood , Edetic Acid/chemistry , Heparin/chemistry , Humans , Limit of Detection
7.
Ann Clin Biochem ; 55(4): 500-504, 2018 Jul.
Article in English | MEDLINE | ID: mdl-28920468

ABSTRACT

Background Analytical comparisons between different high-sensitivity cardiac troponin (hs-cTn) assays are important for reassurance of results performed with different methodologies and to identify potential interferences or confounders to result interpretation. Our objective in the present study was to compare Beckman Coulter's latest hs-cTnI assay to Abbott's hs-cTnI assay and to assess agreement between results. Methods Two hundred ethylenediaminetetraacetic acid plasma samples that had clinically reported hs-cTnI results from the Abbott ARCHITECTi2000 that spanned the analytical range were stored (median = 4 h), re-centrifuged and retested for hs-cTnI on the Abbott ARCHITECTi1000 and Beckman Coulter Access2 analysers. Passing-Bablok regression and fold-differences were evaluated, with differences approximately three-fold between results further subjected to Roche hs-cTnT testing and polyethylene glycol precipitation. Results The Beckman and Abbott hs-cTnI concentrations were correlated ( r = 0.95) with Beckman yielding proportionally lower concentrations (slope = 0.78; 95%CI: 0.74-0.85). There were 12 samples that yielded Abbott hs-TnI concentrations ≥3-fold higher than the Beckman hs-cTnI concentrations; of which nine samples from seven different patients had sufficient quantity for additional testing. All seven patients had macrocomplexes as determined with polyethylene glycol precipitation that affected the Abbott hs-cTnI assay. One patient with Abbott hs-cTnI results >1300 ng/L had polyethylene glycol, heterophile antibodies and creatine kinase-MB testing performed which confirmed that a macrocomplex most likely affected the Abbott and Roche (hs-cTnT = 65 ng/L) assays but not the Beckman (hs-cTnI = 12 ng/L) assay. Conclusion The hs-cTnI concentrations obtained from ethylenediaminetetraacetic acid plasma between the Beckman and Abbott assays are highly correlated, with large differences in concentrations (≥3-fold) between Abbott and Beckman assays possible due to macrocomplexes.


Subject(s)
Myocardial Infarction/blood , Troponin I/blood , Aged , Edetic Acid/chemistry , Female , Humans , Limit of Detection , Male , Middle Aged , Polyethylene Glycols/chemistry , Reproducibility of Results
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