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Information from measurement of levels of inflammatory biomarkers such as procalcitonin (PCT) at the time of admission with radiographic community-acquired pneumonia (CAP) can help to define the need for antibiotic therapy because levels are high with bacterial infection but not with viral infection.
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Measurement of PCT levels on admission and serially can help to define the prognosis of CAP and the likelihood of developing pneumonia complications.
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Serial measurement of PCT levels can be used to
Biomarkers: What is Their Benefit in the Identification of Infection, Severity Assessment, and Management of Community-acquired Pneumonia?
Section snippets
Key points
Available Biomarkers and Their Advantages
Biomarkers include several proinflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1, and IL-6, which can not only reflect the degree of acute inflammation in the patient with CAP but also be direct stimulants of acute-phase reactants such as C-reactive protein (CRP) and PCT (Box 1). The levels of antiinflammatory cytokines can also be measured and include IL-1 receptor antagonist and IL-10. PCT is currently one of the most widely studied biomarkers and is produced in
Predicting Prognosis and Complications
The most widely used prognostic scoring systems are the PSI and modifications of the British Thoracic Society rule, the CURB-65 and CRB-65 scores. Other tools, such as the Infectious Disease Society of America/American Thoracic Society (IDSA/ATS) criteria for severe CAP and the SMART-COP system are designed to assess the severity of illness along with the need for ICU admission or intensive respiratory and vasopressor support.23 These systems are useful for assessing the short-term mortality of
Using biomarkers to guide the duration of CAP therapy
As discussed, measurement of levels of biomarkers, especially PCT, can help clinicians decide when to use antibiotics in a patient with CAP and levels measured at the time of admission, and serially, can help to define prognosis and the likelihood of disease-related complications (Table 1). Because a reduction in PCT indicates a good prognosis and a good response to therapy, several studies have examined whether serial measurements of PCT can be used to define the optimal duration of antibiotic
Conclusions: how and when to use biomarkers in CAP
Biomarkers are a promising tool for the management of CAP and can supplement the information provided by routine clinical assessment and commonly used prognostic scoring tools. Among the available biomarkers, PCT has been studied extensively in recent years, and several clinical trials have established its utility in CAP management, particularly if the highly sensitive Kryptor assay is used. PCT levels can be measured at the time of initial evaluation, and values can help to predict the
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