Validity of the quick-read C-reactive protein test in the prediction of bacterial pneumonia in the pediatric emergency department.

Background: C-reactive protein (CRP) values are clinically useful in differentiating viral from bacterial illnesses in children, but the regular test is impractical in the emergency department (ED) setting.

Objective: To investigate the validity and feasibility of the 2-min bedside Quick Read (QR)-CRP test in the prediction of bacterial pneumonia in children in the ED.

Methods: Fifty randomly selected children aged 4 days to 17 years, who presented to a pediatric ED with symptoms and signs of pneumonia over a 6-month period, were prospectively studied. The diagnosis of bacterial/viral pneumonia was based on clinical and radiological findings. CRP was measured in leftover blood (0.2 ml) using the QR-CRP kit. Clinical and laboratory data were statistically analyzed against CRP values for ability to predict bacterial pneumonia.

Results: Thirty-six patients (72%) were diagnosed with bacterial pneumonia and 14 (28%) with viral pneumonia; mean CRP levels were 121.3+/-122 and 27.2+/-26 mg/l, respectively (P=0.007). Significantly higher CRP levels were associated with bacterial than with viral pneumonia in the patients who presented before 96 h of symptom onset (P=0.013-0.028), but not in those who presented later. On receiver operating characteristics analysis, CRP was a better indicator of a chest radiograph picture of bacterial pneumonia (area under the curve=0.79) than absolute neutrophil count (0.78) or white blood cell count (0.73). Combining all three parameters yielded an area of 0.865.

Conclusion: The QR-CRP test seems to be an useful predictor of bacterial pneumonia in children, especially those with a shorter illness duration, and is feasible for use in the ED.