Estimation of Values below the Limit of Detection of a Contemporary Sensitive Troponin I Assay Improves Diagnosis of Acute Myocardial Infarction
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Estimation of Values below the Limit of Detection of a Contemporary Sensitive Troponin I Assay Improves Diagnosis of Acute Myocardial Infarction. / Boeckel, Jes-Niels; Palapies, Lars; Zeller, Tanja; Reis, Sophia M; von Jeinsen, Beatrice; Tzikas, Stergios; Bickel, Christoph; Baldus, Stephan; Blankenberg, Stefan; Münzel, Thomas; Zeiher, Andreas M; Lackner, Karl J; Keller, Till.
In: CLIN CHEM, Vol. 61, No. 9, 09.2015, p. 1197-1206.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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TY - JOUR
T1 - Estimation of Values below the Limit of Detection of a Contemporary Sensitive Troponin I Assay Improves Diagnosis of Acute Myocardial Infarction
AU - Boeckel, Jes-Niels
AU - Palapies, Lars
AU - Zeller, Tanja
AU - Reis, Sophia M
AU - von Jeinsen, Beatrice
AU - Tzikas, Stergios
AU - Bickel, Christoph
AU - Baldus, Stephan
AU - Blankenberg, Stefan
AU - Münzel, Thomas
AU - Zeiher, Andreas M
AU - Lackner, Karl J
AU - Keller, Till
N1 - © 2015 American Association for Clinical Chemistry.
PY - 2015/9
Y1 - 2015/9
N2 - BACKGROUND: The limit of detection (LoD) is the minimal amount of a substance that can be consistently detected. In the diagnosis of acute myocardial infarction (AMI) many patients present with troponin concentrations below the LoD of contemporary sensitive cardiac troponin I (cs-cTnI) assays. These censored values below the LoD influence the diagnostic performance of these assays compared to highly sensitive cTnI (hs-cTnI) assays. Therefore we assessed the impact of a new approach for interpolation of the left-censored data of a cs-cTnI assay in the evaluation of patients with suspected AMI.METHODS: Our posthoc analysis used a real world cohort of 1818 patients with suspected MI. Data on cs-cTnI was available in 1786 patients. As a comparator the hs-cTnI version of the assay was used. To reconstruct quantities below the LoD of the cs-cTnI assay, a gamma regression approach incorporating the GRACE (Global Registry of Acute Coronary Events) score variables was used.RESULTS: Censoring of cs-cTnI data below the LoD yielded weaker diagnostic information [area under the curve (AUC), 0.781; 95% CI, 0.731-0.831] regarding AMI compared to the hs-cTnI assay (AUC, 0.949; CI, 0.936-0.961). Use of our model to estimate cs-cTnI values below the LoD showed an AUC improvement to 0.921 (CI, 0.902-0.940). The cs-cTnI LoD concentration had a negative predictive value (NPV) of 0.950. An estimated concentration that was to be undercut by 25% of patients presenting with suspected AMI was associated with an improvement of the NPV to 0.979.CONCLUSIONS: Estimation of values below the LoD of a cs-cTnI assay with this new approach improves the diagnostic performance in evaluation of patients with suspected AMI.
AB - BACKGROUND: The limit of detection (LoD) is the minimal amount of a substance that can be consistently detected. In the diagnosis of acute myocardial infarction (AMI) many patients present with troponin concentrations below the LoD of contemporary sensitive cardiac troponin I (cs-cTnI) assays. These censored values below the LoD influence the diagnostic performance of these assays compared to highly sensitive cTnI (hs-cTnI) assays. Therefore we assessed the impact of a new approach for interpolation of the left-censored data of a cs-cTnI assay in the evaluation of patients with suspected AMI.METHODS: Our posthoc analysis used a real world cohort of 1818 patients with suspected MI. Data on cs-cTnI was available in 1786 patients. As a comparator the hs-cTnI version of the assay was used. To reconstruct quantities below the LoD of the cs-cTnI assay, a gamma regression approach incorporating the GRACE (Global Registry of Acute Coronary Events) score variables was used.RESULTS: Censoring of cs-cTnI data below the LoD yielded weaker diagnostic information [area under the curve (AUC), 0.781; 95% CI, 0.731-0.831] regarding AMI compared to the hs-cTnI assay (AUC, 0.949; CI, 0.936-0.961). Use of our model to estimate cs-cTnI values below the LoD showed an AUC improvement to 0.921 (CI, 0.902-0.940). The cs-cTnI LoD concentration had a negative predictive value (NPV) of 0.950. An estimated concentration that was to be undercut by 25% of patients presenting with suspected AMI was associated with an improvement of the NPV to 0.979.CONCLUSIONS: Estimation of values below the LoD of a cs-cTnI assay with this new approach improves the diagnostic performance in evaluation of patients with suspected AMI.
KW - Acute Disease
KW - Aged
KW - Aged, 80 and over
KW - Area Under Curve
KW - Cohort Studies
KW - Female
KW - Humans
KW - Limit of Detection
KW - Male
KW - Middle Aged
KW - Myocardial Infarction/blood
KW - Prognosis
KW - ROC Curve
KW - Regression Analysis
KW - Troponin I/blood
U2 - 10.1373/clinchem.2015.238949
DO - 10.1373/clinchem.2015.238949
M3 - SCORING: Journal article
C2 - 26220065
VL - 61
SP - 1197
EP - 1206
JO - CLIN CHEM
JF - CLIN CHEM
SN - 0009-9147
IS - 9
ER -