Abstract 467 Poster Session III, Monday, 5/3 (poster 218)

Introduction: Procalcitonin (PCT), a propeptide of the hormone calcitonin, becomes elevated in patients with sepsis. However, unlike C-reactive protein, a nonspecific inflammatory marker, PCT's response has been described as being indicative of bacterial infection. We hypothesized that increased PCT levels would identify serious bacterial infection (SBI) in children presenting to the pediatric emergency department (ED) with suspected infection.

Methods: Sera from children presenting to a tertiary-care pediatric ED with clinical signs of infection and later proven to have either a viral infection or SBI was collected and stored at -70°C until time of PCT analysis. Children presenting for routine well-child visits served as controls. As previously reported, PCT levels > 0.5ng/ml and WBC counts <5K or >15K were considered abnormal.

Results: PCT was significantly higher in children with SBI (n=27) compared to those with viral infections (n=25) and controls (n=56) (Figure, table). In this population (n=108), abnormal PCT levels showed a sensitivity of 0.29, specificity of 1.00, positive predictive value (PPV) of 1.00 and negative predictive value (NPV) 0.83 in identifying children with SBI. Among the seven children with elevated serum PCT, five had bacteremia and/or meningitis; one bacterial peritonitis; and one bacterial enteritis. In children with available PCT levels and WBC counts (n=26), the use of abnormal WBC count alone gave a sens. of 0.69, spec. of 0.40, PPV of 0.65 and NPV 0.44 while the addition of an abnormal PCT to WBC count increased sens. to 0.81.

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Table 1 No caption available.
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Conclusion: PCT is highly specific but not very sensitive in distinguishing SBI in the ED. Additional studies with larger patient enrollment are needed to better characterize PCT's clinical utility as an adjunct to WBC counts in the evaluation of children with suspected infection.

This study was funded in part by Brahms Diagnostica GmbH and NIH grant 3M01RR0056GCRC.