Diversity of the elevation of serum cardiac troponin I levels in patients during their first visit to the emergency room.
BACKGROUND
Although measurement of serum creatine kinase levels, as well as myoglobin levels, has been used for screening patients with acute coronary syndrome (ACS), the specificity of both is low. Measurement of cardiac troponin levels is now extensively used for the diagnosis of ACS because of their superior cardiac specificity. However, troponin levels are reportedly elevated not only in patients with ACS but also in those with other diseases.


RESULTS
The clinical characteristics of 1,023 patients (mean age: 63.5+/-16.3 years; males: 665, females: 358) whose serum cardiac troponin I (cTnI) levels had been measured at the initial visit to the emergency room of Toyota Memorial Hospital between April 2004 and March 2005 were retrospectively analyzed. A positive elevation of cTnI was defined as cTnI > or =0.03 ng/ml. There were 432 patients (42.2%) with positive cTnI levels. The cTnI levels (8.48+/-2.64 ng/ml) in patients with acute myocardial infarction (AMI) were greater than those (0.25+/-0.07 ng/ml) in patients with unstable angina pectoris (AP), as well as those (0.04+/-0.01 ng/ml) in patients with stable AP. In terms of the diagnosis of AMI, the sensitivity was high enough (94.6%), but its specificity was relatively low (61.9%). Furthermore, the differentiation between AMI and unstable AP by the cTnI value alone was impossible. The cTnI levels were elevated in patients with a variety of diseases other than ACS, including heart failure, cardiomyopathies, myocarditis, renal failure, tachyarrhythmias, and pulmonary embolism.


CONCLUSIONS
Elevation of the cTnI level is frequently observed in patients in the emergency room with common diseases other than ACS.
Saiki
Atsushi
A
Department of Clinical Laboratory, Toyota Memorial Hospital, Toyota, Japan.
Iwase
Mitsunori
M
Takeichi
Yasushi
Y
Umeda
Hisashi
H
Ishiki
Ryouji
R
Inagaki
Haruo
H
Kato
Yosuke
Y
Nagata
Kohzo
K
Koike
Yasuo
Y
D054058:Acute Coronary Syndrome / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D009202:Cardiomyopathies / Q000097:blood / Q000175:diagnosis / Q000473:pathology; D003402:Creatine Kinase / Q000097:blood; D004636:Emergency Service, Hospital; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009205:Myocarditis / Q000097:blood / Q000175:diagnosis / Q000473:pathology; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D009211:Myoglobin / Q000097:blood; D011237:Predictive Value of Tests; D011655:Pulmonary Embolism / Q000097:blood / Q000175:diagnosis / Q000473:pathology; D051437:Renal Insufficiency / Q000097:blood / Q000175:diagnosis / Q000473:pathology; D012189:Retrospective Studies; D013610:Tachycardia / Q000097:blood / Q000175:diagnosis / Q000473:pathology; D019210:Troponin I / Q000097:blood*
D009211:Myoglobin; D019210:Troponin I; D003402:Creatine Kinase