Increased Concentrations of Cardiac Troponin I Are Equivalent to Increased Cardiac Troponin T in Identifying Chest Pain Patients at Short-Term Risk of Myocardial Infarction

Background Patients with chronic kidney disease often have increased plasma cardiac troponin concentration in the absence of myocardial infarction. Incidence of myocardial infarction is high in this population, and diagnosis, particularly of non ST-segment elevation myocardial infarction (NSTEMI), is challenging. Knowledge of biological variation aids understanding of serial cardiac troponin measurements and could improve interpretation in clinical practice. The National Academy of Clinical Biochemistry (NACB) recommended the use of a 20% reference change value in patients with kidney failure. The aim of this study was to calculate the biological variation of cardiac troponin I and cardiac troponin T in patients with moderate chronic kidney disease (glomerular filtration rate [GFR] 30–59 mL/min/1.73 m2). Methods and results Plasma samples were obtained from 20 patients (median GFR 43.0 mL/min/1.73 m2) once a week for four consecutive weeks. Cardiac troponin I (Abbott ARCHITECT® i2000SR, median 4.3 ng/L, upper 99th percentile of reference population 26.2 ng/L) and cardiac troponin T (Roche Cobas® e601, median 11.8 ng/L, upper 99th percentile of reference population 14 ng/L) were measured in duplicate using high-sensitivity assays. After outlier removal and log transformation, 18 patients’ data were subject to ANOVA, and within-subject (CVI), between-subject (CVG) and analytical (CVA) variation calculated. Variation for cardiac troponin I was 15.0%, 105.6%, 8.3%, respectively, and for cardiac troponin T 7.4%, 78.4%, 3.1%, respectively. Reference change values for increasing and decreasing troponin concentrations were +60%/–38% for cardiac troponin I and +25%/–20% for cardiac troponin T. Conclusions The observed reference change value for cardiac troponin T is broadly compatible with the NACB recommendation, but for cardiac troponin I, larger changes are required to define significant change. The incorporation of separate RCVs for cardiac troponin I and cardiac troponin T, and separate RCVs for rising and falling concentrations of cardiac troponin, should be considered when developing guidance for interpretation of sequential cardiac troponin measurements.

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Autoantibody prevalence with an improved immunoassay for detecting cardiac troponin-specific autoantibodies

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2013-0310 ◽

2014 ◽

Vol 52 (2) ◽

Cited By ~ 7

Author(s):

Tanja Savukoski ◽

Tuomo Ilva ◽

Juha Lund ◽

Pekka Porela ◽

Noora Ristiniemi ◽

...

Keyword(s):

Myocardial Infarction ◽

Emergency Department ◽

Chest Pain ◽

Cardiac Troponin ◽

Troponin I ◽

State Of The Art ◽

Cardiac Troponin I ◽

High Prevalence ◽

Sandwich Type ◽

Pain Patients

AbstractCardiac troponin-specific autoantibodies (cTnAAb) can interfere with the measurement of cardiac troponin I (cTnI) by immunoassays used for the diagnosis of myocardial infarction (MI). Here, an improved version of a previous autoantibody assay was validated and used to evaluate the cTnAAb prevalence in a cohort of consecutive chest pain patients presenting to an emergency department.Admission samples from 510 patients with suspected MI were analyzed in parallel with two sandwich-type cTnAAb assays based on different cTnI epitopes used to capture cardiac troponin-bound cTnAAbs.Sample-specific backgrounds were lower for the new assay than for the old assay (median 1225 vs. 2693 counts, p<0.001). Net signals of cTnAAb-positive samples were higher for the new assay than for the old assay (median 5076 vs. 3921 counts, p<0.001). Of all patients, 9.2% were cTnAAb-positive for the new assay and 7.3% for the old assay (p=0.013). Previous cardiac problems were not associated with cTnAAb status and cTnAAb status did not correlate with the 12-month outcome.With our new and more sensitive autoantibody assay, approximately one out of ten patients who presented to the initial cardiac triage had detectable amounts of cTnAAbs in the circulation. Because these cTnAAbs can interfere with state-of-the-art cTnI assays, their high prevalence should be acknowledged by clinical chemists, physicians, and kit manufacturers.

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IMPACT OF MARKEDLY ELEVATED INITIAL HIGH-SENSITIVITY CARDIAC TROPONIN T ON PREDICTION OF ACUTE MYOCARDIAL INFARCTION IN CHEST PAIN PATIENTS AND ADDITIONAL VALUE OF KINETIC CHANGES: RESULTS FROM THE TRAPID-AMI STUDY

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(15)60133-4 ◽

2015 ◽

Vol 65 (10) ◽

pp. A133

Author(s):

Matthias Mueller ◽

Christian Mueller ◽

Evangelos Giannitsis ◽

Moritz Biener ◽

Mehrshad Vafaie ◽

...

Keyword(s):

Myocardial Infarction ◽

Acute Myocardial Infarction ◽

Chest Pain ◽

Cardiac Troponin ◽

Troponin T ◽

High Sensitivity ◽

Cardiac Troponin T ◽

Additional Value ◽

Pain Patients

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Serial Sampling of High-Sensitivity Cardiac Troponin T May Not Be Required for Prediction of Acute Myocardial Infarction Diagnosis in Chest Pain Patients with Highly Abnormal Concentrations at Presentation

Clinical Chemistry ◽

10.1373/clinchem.2016.258392 ◽

2017 ◽

Vol 63 (2) ◽

pp. 542-551 ◽

Cited By ~ 26

Author(s):

Matthias Mueller-Hennessen ◽

Christian Mueller ◽

Evangelos Giannitsis ◽

Moritz Biener ◽

Mehrshad Vafaie ◽

...

Keyword(s):

Myocardial Infarction ◽

Acute Myocardial Infarction ◽

Chest Pain ◽

Cardiac Troponin ◽

Troponin T ◽

High Sensitivity ◽

Final Diagnosis ◽

Cardiac Troponin T ◽

Blood Concentrations ◽

Pain Patients

Abstract BACKGROUND Guidelines for diagnosing acute myocardial infarction (AMI) recommend adding kinetic changes to the initial cardiac troponin (cTn) blood concentration to improve AMI diagnosis. We hypothesized that kinetic changes may not be required in patients presenting with highly abnormal cTn. METHODS Patients presenting with suspected AMI to the emergency department were enrolled in a prospective diagnostic study. We assessed the positive predictive value (PPV) of initial high-sensitivity cardiac troponin T (hs-cTnT) blood concentrations alone and in combination with kinetic changes for AMI. Predefined relative changes (δ change of ≥20%) and absolute changes (Δ change ≥9.2 ng/L) within different time intervals (1 h, 2 h, and 4–14 h after presentation) were assessed. The final diagnosis was adjudicated by 2 independent cardiologists. RESULTS Among 1282 patients, 213 (16.6%) patients had a final diagnosis of AMI. For AMI prediction, PPVs increased from 48.8% for an initial hs-cTnT >14 ng/L to 87.2% for >60 ng/L, whereas PPVs remained unchanged for higher hs-cTnT concentrations at baseline (87.1% for both >80 ng/L and >100 ng/L). With addition of 20% relative Δ change, PPVs were not further improved in patients with baseline hs-cTnT >80 ng/L using the 1-h (84.0%) and 2-h (88.9%) intervals, and only minimally when extending the interval to 4–14 h (91.2% for >80 ng/L and 90.4% for >100 ng/L, respectively). Similar findings were observed when applying absolute changes. CONCLUSIONS In chest pain patients with highly abnormal hs-cTnT concentrations at presentation, subsequent blood draws may not be required, as they do not provide incremental diagnostic value for prediction of AMI diagnosis.

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