title: Role of procalcitonin in managing adult patients with respiratory tract infections.
abstract: Respiratory infections remain the most common reason why patients seek medical care in ambulatory and hospital settings, and they are the most frequent precursor of sepsis. In light of the limitations of clinical signs and symptoms and traditional microbiologic diagnostics for respiratory infections, blood biomarkers that correlate with the presence and extent of bacterial infections may provide additional useful information to improve diagnostic and prognostic efforts and help with therapeutic decisions in individual patients. A growing body of evidence supports the use of procalcitonin (PCT) to differentiate bacterial from viral respiratory diagnoses, to help risk stratify patients, and to guide antibiotic therapy decisions about initial need for, and optimal duration of, therapy. Although still relatively new on the clinical frontier, a series of randomized controlled trials have evaluated PCT protocols for antibiotic-related decision making and have included patients from different clinical settings and with different severities of respiratory infection. In these trials, initial PCT levels were effective in guiding decisions about the initiation of antibiotic therapy in lower-acuity patients, and subsequent measurements were effective for guiding duration of therapy in higher-acuity patients, without apparent harmful effects. Recent European respiratory infection guidelines now also recognize this concept. As with any other laboratory test, PCT should not be used on a stand-alone basis. Rather, it must be integrated into clinical protocols, together with clinical, microbiologic data and with results from clinical risk scores. The aim of this review is to summarize recent evidence about the usefulness of PCT in patients with lower respiratory tract infections and to discuss the potential benefits and limitations of this marker when used for clinical decision making.
authors.affiliation: Harvard School of Public Health, Massachusetts General Hospital, Boston, MA; Department of Medicine, Massachusetts General Hospital, Boston, MA. Electronic address: Schuetzph@gmail.com.
authors.forename: Philipp
authors.initials: P
authors.lastname: Schuetz
authors.affiliation: Department of Medicine, Massachusetts General Hospital, Boston, MA; Medical/Surgical ICU, Morton Plant Hospital, Clearwater, FL.
authors.forename: Devendra N
authors.initials: DN
authors.lastname: Amin
authors.affiliation: Inpatient Clinician Educator Service, Massachusetts General Hospital, Boston, MA; Department of Medicine, Massachusetts General Hospital, Boston, MA.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Greenwald
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001424:Bacterial Infections / Q000175:diagnosis / Q000188:drug therapy; D015415:Biomarkers / Q000097:blood; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D003362:Cost-Benefit Analysis; D003365:Costs and Cost Analysis; D006801:Humans; D011379:Prognosis; D011498:Protein Precursors / Q000097:blood*; D012141:Respiratory Tract Infections / Q000188:drug therapy / Q000191:economics / Q000382:microbiology*; D014777:Virus Diseases / Q000175:diagnosis / Q000188:drug therapy
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide