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Diagnostic markers for community-acquired pneumonia
1Department of Respiratory Medicine, Ohara Healthcare Foundation, Kurashiki Central Hospital, Kurashiki, Okayama, Japan.
Abstract:
Community-acquired pneumonia (CAP) is one of the respiratory infectious diseases caused by not only bacteria, but also viruses. Antibiotic agents are needed to treat only bacterial but not viral CAP. In addition, there are some non-infectious respiratory diseases in the differential diagnosis of CAP, such as malignant diseases, interstitial lung diseases, pulmonary edema, and pulmonary hemorrhage. We usually diagnose patients having CAP by comprehensive evaluation of symptoms, vital signs, laboratory examinations, and radiographic examinations. However, symptoms and vital signs are not specific for the diagnosis of CAP; therefore, we also use inflammatory biomarkers for differentiating bacterial from viral CAP and non-infectious respiratory diseases. We have used the white blood cell count, C-reactive protein (CRP), and erythrocyte sedimentation rate as common inflammatory biomarkers, but they are not specific for bacterial infection because they could be increased by malignant diseases and collagen diseases. Recently, some inflammatory biomarkers such as procalcitonin (PCT), soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), pro-adrenomedullin (proADM), and presepsin have been developed as relatively specific biomarkers for bacterial infection. Many reports have evaluated the usefulness of PCT for diagnosing CAP. In this review, the characteristics of each biomarker are discussed based on previous studies.
Insights
Diagnosing community-acquired pneumonia (CAP) requires differentiating bacterial from viral infections and non-infectious diseases. Newer biomarkers like procalcitonin (PCT) show promise for specific bacterial infection detection in CAP.
Area of Science:
- Pulmonary Medicine
- Infectious Diseases
- Biomarker Research
Background:
- Community-acquired pneumonia (CAP) presents diagnostic challenges due to diverse causes (bacterial, viral, non-infectious).
- Traditional inflammatory biomarkers (WBC, CRP, ESR) lack specificity for bacterial CAP, often elevated in other conditions.
- Accurate differentiation is crucial for appropriate antibiotic use and patient management.
Purpose of the Study:
- To review and discuss the characteristics of emerging inflammatory biomarkers for diagnosing CAP.
- To evaluate the utility of newer biomarkers in differentiating bacterial CAP from viral CAP and non-infectious respiratory diseases.
- To highlight the potential of biomarkers like procalcitonin (PCT) in CAP diagnosis.
Main Methods:
- Literature review of studies evaluating inflammatory biomarkers in CAP.
- Analysis of biomarker characteristics, including specificity and sensitivity for bacterial infection.
- Comparison of novel biomarkers (PCT, sTREM-1, proADM, presepsin) with traditional markers.
Main Results:
- Novel biomarkers such as procalcitonin (PCT), soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), pro-adrenomedullin (proADM), and presepsin demonstrate higher specificity for bacterial infections.
- Procalcitonin (PCT) has been extensively studied for its role in CAP diagnosis and differentiating bacterial from viral etiologies.
- Traditional biomarkers show limitations in specificity, being elevated in non-infectious inflammatory conditions.
Conclusions:
- Emerging biomarkers offer improved accuracy in diagnosing bacterial CAP compared to traditional markers.
- Procalcitonin (PCT) is a key biomarker for guiding antibiotic therapy decisions in CAP.
- Further research into biomarker panels may enhance diagnostic precision for respiratory diseases.
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