Diagnostic and prognostic role of cardiac troponin I (cTnI) measured on the DPC Immulite (original) (raw)

The value of cardiac Troponin-I as a biochemical marker of acute coronary syndromes compared with other traditional markers

The aim of the present study was to assess the clinical values of serum total Creatine Kinase (Total-CK), Creatine Kinase-MB isoenzyme (CK-MB) and total Lactate Dehydrogenase (LDH) compared with cardiac Troponin-I (cTnI) in the diagnosis of acute coronary syndromes (ACS). The study was carried on 27 patients with acute coronary syndromes from the intensive care unit (ICU) of the Egyptian National Heart Institute (NHI), Imbaba, Giza, Egypt, in addition to 9 healthy age matched subjects served as controls. Patients were classified into 3 groups: Unstable angina group, acute myocardial infarction group with ST-segment elevation and myocardial infarction group with non ST-segment elevation. Blood samples have been taken from the patients on admission to NHI (ICU) and at 24 and 48 hours after their admission. Serum Total-CK, CK-MB, LDH were determined spectrophotometrically and cTnI was determined using Enzyme Linked Immunosorbent Assay (ELISA). The obtained results revealed that there was a positive significant correlation between cTnI and the other biochemical markers except with LDH on admission to NHI (ICU). Percent sensitivity was also determined. On admission both cTnI and CK-MB showed the highest sensitivity (59 %) while after 24 hours of admission, cTnI showed the highest sensitivity (85 %) and after 48 hours of admission LDH showed the highest sensitivity (77 %). Specificity level 100%. In conclusion, the present study showed that cTnI was the most sensitive biochemical marker than the other traditional biochemical markers (Total-CK, CK-MB, and LDH) for establishing the diagnosis of ACS during the first 48 hours after admission to the hospital. It is better, however to use a combination of more than one marker in the diagnosis of Acute Coronary Syndrome.

The value of cardiac troponin-i as a biochemical markers of acute coronary syndromes compared with other traditional markers

Bulletin of Egyptian Society for Physiological Sciences

The aim of the present study was to assess the clinical values of serum total Creatine Kinase (Total-CK), Creatine Kinase-MB isoenzyme (CK-MB) and total Lactate Dehydrogenase (LDH) compared with cardiac Troponin-I (cTnI) in the diagnosis of acute coronary syndromes (ACS). The study was carried on 27 patients with acute coronary syndromes from the intensive care unit (ICU) of the Egyptian National Heart Institute (NHI), Imbaba, Giza, Egypt, in addition to 9 healthy age matched subjects served as controls. Patients were classified into 3 groups: Unstable angina group, acute myocardial infarction group with ST-segment elevation and myocardial infarction group with non ST-segment elevation. Blood samples have been taken from the patients on admission to NHI (ICU) and at 24 and 48 hours after their admission. Serum Total-CK, CK-MB, LDH were determined spectrophotometrically and cTnI was determined using Enzyme Linked Immunosorbent Assay (ELISA). The obtained results revealed that there was a positive significant correlation between cTnI and the other biochemical markers except with LDH on admission to NHI (ICU). Percent sensitivity was also determined. On admission both cTnI and CK-MB showed the highest sensitivity (59 %) while after 24 hours of admission, cTnI showed the highest sensitivity (85 %) and after 48 hours of admission LDH showed the highest sensitivity (77 %). Specificity level 100%. In conclusion, the present study showed that cTnI was the most sensitive biochemical marker than the other traditional biochemical markers (Total-CK, CK-MB, and LDH) for establishing the diagnosis of ACS during the first 48 hours after admission to the hospital. It is better, however to use a combination of more than one marker in the diagnosis of Acute Coronary Syndrome.

Analytical and diagnostic performance of troponin assays in patients suspicious for acute coronary syndromes

Clinical Biochemistry, 2000

The controversy whether there is a clinically significant difference between troponin T (cTnT) and troponin I (cTnI) in regard to predictive value and cardiac specificity is still ongoing. Methods: We evaluated enzyme-linked immunosorbent assay systems for cTnI and cTnT in patients with acute coronary syndromes and multiple control groups to define threshold values for risk stratification and compare their predictive value. Results: In 312 patients with noncardiac chest pain, cTnI levels were below the detection limit of 0.2 g/L and cTnT levels were 0.011 [0.010 -0.013] g/L. In patients with end-stage renal failure (n ϭ 26) and acute (n ϭ 38) or chronic (n ϭ 16) skeletal muscle damage, median concentrations were 0.20 [0.20 -0.35], below the detection limit, and 0.20 [0.20 -0.25] for cTnI, and 0.04 [0.01-0.10], 0.011 [0.005-0.025], and 0.032 [0.009 -0.054] g/L for cTnT. In patients with acute coronary syndromes (n ϭ 1130), maximized prognostic value for 30-day outcome (death, infarction) was observed at a threshold level of 1.0 g/L for cTnI (29.0% positive) and at 0.06 g/L for cTnT (35.0% positive). Significant differences in the area-under-the-curve values were observed between cTnI and cTnT (0.685 vs. 0.802; p ϭ 0.005). For both markers, the area-under-thecurve values did not increase with the second (within 24 h after enrollment) or third (48 h) blood draw. CTnI showed a less strong association with 30-day outcome than cTnT. When cTnI was put in a logistic multiple-regression model first, cTnT did add significant information. Conclusion: By using the defined threshold values and the employed test systems, single testing for cTnI and cTnT within 12 h after symptom onset was appropriate for risk stratification. Despite the lower cardiac specificity for cTnT, it appears to have a stronger association with the patients' outcome, whereas, as previously shown, the ability to identify patients who benefit from treatment with a GP IIb/IIIa receptor antagonist is similar.

Use of the bioMérieux VIDAS® troponin I ultra assay for the diagnosis of myocardial infarction and detection of adverse events in patients presenting with symptoms suggestive of acute coronary syndrome

Clinica Chimica Acta, 2008

Background: We demonstrate the performance of the bioMérieux VIDAS Troponin I Ultra assay for diagnostic accuracy for detection of myocardial infarction (MI) and risk stratification. Method: cTnI was measured in 545 patients from 2 clinical centers with symptoms suggestive of ACS at admission, with an additional specimen at 4-12 h (453 patients). The 99th percentile value (0.01 µg/l) was used to assess clinical accuracy for diagnosis of acute MI. Primary endpoint for risk stratification was first of cardiac event or death in 302 patients (one center) followed for 60 days. Results: 157 (28.8%) patients ruled in for an MI during index hospitalization. Sensitivities and specificities were 88.1% (95% CI 81.9 to 92.4%) and 79.9% (CI 75.5 to 83.6%) for baseline and 100% (CI 96.5 to 100%) and 79.4% (CI 74.4 to 83.4%) for follow-up specimens. ROC curve areas increased from 0.912 (CI 0.879 to 0.944) at baseline to 0.994 (CI 0.988 to 0.999) at second sampling (n = 453, p b 0.01); with no differences between sites. Primary endpoint rate for the 223 patients (74%) with normal cTnI on presentation was lower than the 79 patients (26%) with cTnI N 0.01 ug/l (5.9% vs. 42.3%, p b 0.0001). The relative risk for the N 0.01 ug/l group was 8.9 (CI 4.6 to 17). Conclusion: The VIDAS cTnI assay is a sensitive diagnostic method for the early detection of MI and predicts increased risk for adverse events in patients with symptoms suggestive of ACS.

Diagnostic accuracy of a point-of-care troponin I assay for acute myocardial infarction within 3 hours after presentation in early presenters to the emergency department with chest pain

American Heart Journal, 2012

Background Guidelines recommend that serial cardiac marker testing to rule out acute myocardial infarction (AMI) be performed for 8 to 12 hours after symptom onset. We aim to determine the diagnostic accuracy of a contemporary point-ofcare (POC) troponin I (TnI) assay within 3 hours for patients presenting within 8 hours of symptom onset. Methods The MIDAS study collected blood from patients presenting with suspected acute coronary syndrome at presentation and at 90 minutes, 3 hours, and 6 hours in whom the emergency physician planned an objective cardiac ischemia evaluation. Criterion standard diagnoses were adjudicated by experienced clinicians using all available medical records per American Heart Association/American College of Cardiology criteria. Reviewers were blinded to the investigational marker, Cardio3 TnI POC. The Cardio3 TnI reference value was defined as N0.05 ng/mL. Measures of diagnostic accuracy are presented with 95% CI. Results A total of 858 of 1107 patients met the inclusion criteria. The study cohort had 476 men (55.5%) with median age of 57.0 years (interquartile range 48.0-67.0 years). Median time from symptom onset to initial blood draw was 3.9 hours (interquartile range 2.7-5.2 hours). Acute myocardial infarction was diagnosed in 82 patients (9.6%). The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio over 3 hours were 84.1, 93.4, 12.8, and 0.17, respectively. There was no significant improvement in diagnostic accuracy associated with adding 6-hour serial testing to the 3-hour sample. Conclusion In suspected patients with acute coronary syndrome presenting to the emergency department within 8 hours of symptom onset, 3 hours of serial testing with the Cardio3 TnI POC platform provides similar diagnostic accuracy for AMI as longer periods.

The new high-sensitivity cardiac troponin T assay improves risk assessment in acute coronary syndromes

American Heart Journal, 2010

Background Cardiac troponins are currently the markers of choice for diagnosis of acute myocardial infarction and risk assessment in acute coronary syndrome (ACS). With the introduction of the new high-sensitivity cardiac troponin T (hs-cTnT) assay, it has become possible to measure cTnT even in healthy subjects. However, how the hs-cTnT assay compares with the old cTnT assay for risk assessment in ACS is still unknown. Methods Cardiac troponin T levels were measured with the new hs-cTnT assay and the old third-generation cTnT assay in serum samples collected 48 hours after randomization in 1,452 randomly selected ACS patients enrolled in the GUSTO-IV trial. During 30 days of follow-up, deaths and myocardial infarctions were recorded. At 12 months, only all-cause mortality was collected. Results The 16% of the patients that had levels higher than the 99th percentile cutoff for hs-cTnT but less than for cTnT had a similar 1-year mortality as the 60% that were positive for both assays (9.2% vs 10.7%, P = .52) and a higher 1-year mortality compared with the 24% that were negative for both assays (9.2% vs 2.6%, P = .001). For death or acute myocardial infarction at 30 days, the group that was positive only for hs-cTnT had an intermediate risk compared with the groups negative or positive for both assays (2.4%, 5.2%, and 8.7%; P b .001). Conclusion The new hs-cTnT assay, compared with the old cTnT assay, identified more patients with myocardial damage and who were at an increased risk for new cardiac events.

Use of cardiac troponins as strong markers for patients with acute coronary syndrome

Rangsit University, 2014

Acute myocardial infarction (AMI) is the most important cause of cardiomyocyte necrosis. Cardiac troponin (cTn) T and I are structural proteins unique to the heart and have been used as the preferred cardiac biomarkers in the universal definition of myocardial infarction. Cardiac troponins have demonstrated nearly absolute myocardial tissue specificity and high clinical sensitivity for myocardial ischemia. The recent development of high-sensitivity cardiac troponin (hs-cTn) assays allows detection of very low levels of cTn. The hs-cTn assays have improved the diagnostic accuracy and rapid detection of myocardial infarction. Undetectable hs-cTn rules out AMI with a negative predictive value > 99% on emergency department admission. The diagnosis of acute myocardial damage requires a significant change with serial hs-cTn testing. Current consensus for rapid rule-in proposed a 20% increase within 3 to 6 hours when baseline cTn levels are elevated. In addition, relative increases > 50% above the 99 th percentile upper reference limit are found to be the diagnosis of AMI, in the case of negative baseline value. Besides relative change, the absolute values of hs-cTn at emergency department presentation in patients with suspected AMI should be considered as important criteria in the differential diagnosis of the cause of cardiomyocyte damage. Cardiac troponins provide both diagnostic and prognostic information in the setting of acute coronary syndrome (ACS). Elevation of cTn in the absence of ACS should prompt an evaluation for non-thrombotic mechanism of increased cTn levels and direct management at the underlying cause.