Serum procalcitonin, C-reactive protein and interleukin-6 for distinguishing bacterial and viral pneumonia in children.
OBJECTIVE
Serum procalcitonin (PCT), C-reactive protein (CRP) and interleukin-6 (IL-6) concentrations were measured in 126 children hospitalized for community-acquired, radiologically confirmed pneumonia to assess whether these host response values could be used to distinguish bacterial from viral pneumonia.


METHODS
The samples for PCT, CRP and IL-6 measurements were obtained on admission or the first day of hospitalization. The etiology of pneumonia was studied with an extensive panel of methods that detected 6 bacteria and 11 viruses.


RESULTS
In all, 54% had evidence of bacterial pneumonia, and 32% had evidence of sole viral pneumonia. In 14% of the cases the etiology could not be determined. Children with bacterial pneumonia had significantly higher PCT (median 2.09 ng/ml vs. 0.56 ng/ml, P = 0.019) and CRP concentrations (96 mg/l vs. 54 mg/l, P = 0.008) than those with sole viral etiology. However, the values markedly overlapped. No significant difference in IL-6 concentrations was seen between the two patient groups. Using PCT > or = 2.0 ng/ml, CRP > or = 150 mg/l or IL-6 > or = 40 pg/ml, the specificity was > or =80% for bacterial pneumonia. The sensitivities with these cutoff values were 50% for PCT, 31% for CRP and 34% for IL-6.


CONCLUSIONS
The results indicate that the measurement of serum PCT, CRP and IL-6 has little value in the differentiation of bacterial and viral pneumonia in children. However, in some patients with very high serum PCT, CRP or IL-6 values, bacterial pneumonia is probable.
Department of Pediatrics, Turku University Hospital, Finland. pia.toikka@utu.fi
P
P
Toikka
K
K
Irjala
T
T
Juvén
R
R
Virkki
J
J
Mertsola
M
M
Leinonen
O
O
Ruuskanen
D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis*; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D002648:Child; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000097:blood / Q000175:diagnosis; D003937:Diagnosis, Differential; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D018410:Pneumonia, Bacterial / Q000097:blood / Q000175:diagnosis*; D011024:Pneumonia, Viral / Q000097:blood / Q000175:diagnosis*; D011498:Protein Precursors / Q000097:blood*; D012680:Sensitivity and Specificity
D015415:Biomarkers; C000606589:CALCA protein, human; D015850:Interleukin-6; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide