The use of CRP for diagnosing infections in young infants < 3 months of age in developing countries.

The diagnosis of severe bacterial infection in young infants in developing countries is difficult because of the lack of sensitivity and specificity of the presenting symptoms and signs. Whether C-reactive protein (CRP) might help with the early detection of neonatal sepsis was investigated in a prospective study in The Gambia, Ethiopia and The Philippines. Infants < 3 months of age with symptoms or signs of possible sepsis were evaluated; CRP was measured and assessed for its ability to predict proven invasive bacterial infection. Of 966 children < 3 months of age, 54 had a positive blood culture, 13 a positive CSF culture, 15 a positive blood and CSF culture and 884 had negative cultures. Median (interquartile range) CRP values were 42 (9-173), 14 (6-36), 209 (135-286) and 8 (3-27) mg/L in the four groups, respectively. Taking a CRP cut-off of 10 mg/L, the sensitivity and specificity of an elevated CRP to predict a positive blood or CSF culture were 77% and 55%, respectively, and 55% and 82%, respectively, for a cut-off of 40 mg/L. CRP lacks the sensitivity and specificity to be used alone as a predictor of serious infections in young infants.