Korean J Lab Med.  2008 Oct;28(5):339-345. 10.3343/kjlm.2008.28.5.339.

Clinical Significance of Minor Elevation of Cardiac Troponin I

• Jung CL
• Cho SE
• Hong KS

• KMID: 1781565
• DOI: http://doi.org/10.3343/kjlm.2008.28.5.339

Abstract

BACKGROUND: Cardiac troponin I (cTnI) is known as a sensitive and specific marker for myocardial ischemia. The purposes of this study are to establish cut-off values of cTnI for acute myocardial infarction (AMI) and to analyze clinical significance of minor elevation of cTnI.
METHODS
Two hundred and four patients from whom cTnI was measured at Ewha Womans University Dongdaemun hospital from January to March, 2006 were enrolled in the study. cTnI was measured using Dimension RxL (Dade Behring, USA). The lower limit of detection (LLD), 10% CV value, 99th percentile of healthy individuals, and cut-off value for AMI by ROC curve analysis were determined.
RESULTS
LLD, 10% CV value, and 99th percentile of cTnI were 0.00 ng/mL, 0.10 ng/mL, and 0.07 ng/mL, respectively. The cut-off value of peak cTnI for AMI by ROC curve analysis was 0.13 ng/mL with the sensitivity, specificity, and AUC of 90.9%, 87.7%, and 0.921, respectively. The peak value of cTnI of patients with ischemic heart disease (IHD) was higher than that of the patients without IHD (P<0.05). According to the above reference and cut-off values of the initial cTnI, patients were categorized into four groups; < or =0.05 ng/mL (group 1), 0.06-0.09 ng/mL (group 2), 0.10-0.59 ng/mL (group 3), > or =0.60 ng/mL (group 4), and compared frequencies of AMI, IHD, cardio vascular disease (CVD) and death after 1 month among groups. Frequencies of AMI, IHD, CVD, and death after 1 month were significantly increased as the cTnI concentrations were increased (P<0.05).
CONCLUSIONS
Minor elevation of cTnI value, even in group 3 was significantly associated with high incidence of AMI, IHD, CVD, and death rate after 1 month.

Keyword

99th percentile of cTnI; 10% CV of cTnI; AMI cut-off value

MeSH Terms

Acute Disease
Aged
Aged, 80 and over
Biological Markers/blood
Cardiovascular Diseases/*diagnosis/etiology/mortality
Data Interpretation, Statistical
Female
Humans
Male
Middle Aged
Myocardial Infarction/*diagnosis/etiology/mortality
Myocardial Ischemia/diagnosis/etiology/mortality
Predictive Value of Tests
ROC Curve
Sensitivity and Specificity
Survival Analysis
Troponin I/*blood

Figure

• 

  Fig. 1. Total precision profile for cardiac troponin I (cTnI). The 10% CV value was 0.10 ng/mL.

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  Fig. 2. ROC curve for cTnI in 204 patients with or without AMI.

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