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KEY POINTS
An ideal biomarker has a high sensitivity and allows for clinical applications in the diagnosis, staging, prognosis, and treatment of disease.
Early identification of ischemia after the rupture or erosion of an atherosclerotic coronary plaque and before myonecrosis occurs is currently under investigation. Biomarkers of myocardial ischemia include choline, a chemical released during membrane damage; unbound free fatty acids, a chemical released by ischemic myocytes and ischemia-modified albumin.
The cardiac biomarkers B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are elevated in 80% of patients who present to the emergency department (ED) with chronic heart failure (CHF).
Neutrophil gelatinase-associated lipocalin (NGAL) is a novel serum biomarker that can identify acute kidney injury (AKI) early after the initial renal insult and can be reliably measured in the plasma by point-of-care immunoassay. NGAL levels were elevated up to 48 hours prior to the diagnosis of AKI based on the risk or renal dysfunction, injury to the kidney, failure of kidney function, loss of kidney function, and end-stage kidney disease (RIFLE) criteria in a recent study.
The use of procalcitonin (PCT) in the diagnosis and discrimination of bacterial infection, sepsis, and response to antibiotic therapy from noninfectious causes of systemic inflammatory response syndrome (SIRS) (ie, pancreatitis) is currently in use by some institutions.
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A biological marker (biomarker) is a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention.1 An ideal biomarker enables sensitivity and allows for clinical applications in the diagnosis, staging, prognosis, and treatment of disease. The utility of biomarkers in clinical decision making can be organized into a multitude of categories (Figure 7–1). Diagnostic biomarkers may afford rapid screening and stratification of patients into specific groups that may respond to a particular intervention or treatment. Prognostic biomarkers may predict the course or trajectory of disease allowing for early determination of disposition (ie, floor vs ICU) and goals of care. Surrogate biomarkers are those, which are substituted for a clinical end point (ie, response to therapy).
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Since 1900 (with exception of 1918), cardiovascular disease has been the leading cause of mortality in the United States.2 In 2009, statistics indicated that cardiovascular disease accounted for approximately 800,000 or 32% of deaths annually. Coronary heart disease also remains the ...