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 272 +/- 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.