CRP Levels Predict Nosocomial Infections

A new study suggests that daily monitoring of C-reactive protein (CRP) levels could help in the prediction of infections acquired in the intensive care unit.

Dr. Pedro Povoa and colleagues from the Hospital Garcia de Orta (Almada, Portugal) analyzed the CRP levels of patients admitted to their intensive care unit (ICU) during 72 hours or more. Among the patients selected for the study, 35 acquired an infection during their stay at the ICU and 28 did not. Infected patients were those who had a documented ICU-acquired infection and were not receiving antibiotics for at least five days before diagnosis. Noninfected patients never received antibiotics and were discharged. The researchers analyzed the patients' records of CRP levels during the five days before diagnosis of infection or ICU discharge, respectively.

Results showed that a daily variation of CRP levels greater than 4.1 mg/dl is a good marker for prediction of infection, with 92.1% sensitivity and 71.4% specificity. If combined with a CRP concentration greater than 8.7 mg/dl, the prediction power increased even further. Eight-eight percent of patients with a daily variation of CRP levels greater than 4.1 mg/dl and a CRP concentration greater than 8.7 mg/dl developed an infection. Dr. Povoa and coworkers concluded that monitoring CRP progression could help in clinical decision-making and the prescription of antibiotics. The findings were published in the April 2006 issue of the journal Critical Care.

CRP is an acute-phase protein, stably conserved throughout vertebrate evolution, suggesting a central role in immunologic response. It is synthesized in the liver and binds to polysaccharides of pathogens promoting phagocytosis. CRP measurement is a rapid, reproducible, and inexpensive test.