Study objective: To evaluate measurement of interleukin-6 as a diagnostic test for the presence and severity of invasive bacterial disease.
Design: Prospective measurement of interleukin-6 in children with signs of sepsis. (Controls, retrospective from serum bank.)
Setting: Emergency department of an urban children's hospital.
Participants: Twenty children with clinical signs of sepsis and 50 other febrile infants and toddlers with negative blood cultures.
Results: Eleven of the 213 patients had bacteriologically documented infections: four with meningitis and two with bacteremia caused by Neisseria meningitidis, three with meningitis caused by Haemophilus influenzaetype b, and one each with meningitis and bacteremia caused by Streptococcus pneumoniae. Ten of these 13 had detectible interleukin-6. The geometric mean interleukin-6 level in these culture-positive patients was 4137 pg/mL (95% confidence interval, 1138 to 1,545): all three children with levels of more than 3013 pg/mL developed septic shock, and one died. One of nine culture-negative patients with clinical signs of sepsis had detectable serum interleukin-6 (366 pg/mL), but none of 50 other febrile children without occult bacteremia did. The detection of interleukin-6 had a sensitivity of 93 % and a specificity of 98% for invasive bacterial disease.
Conclusion: High levels of interleukin-6 occur in children with septic shock, and the presence of intarleukin-6 in serum is predictive for the isolation of bacteria from blood and/or spinal fluid.