brand logo

Am Fam Physician. 2004;69(4):955

Many physicians use a white blood cell count to screen for infection in infants with fever. Studies have found that white blood cell count analysis is not accurate in screening infants for bacterial meningitis and urinary tract infection; its efficacy in screening for bacteremia also has been questioned. Because infants' immune systems are immature, data from studies of older children cannot be extrapolated. Bonsu and Harper reviewed the records of infants younger than 90 days with a temperature of at least 38°C (100.4°F) who were treated in an urban pediatric emergency department.

Infants with acute leukemia were excluded from the study. If a blood culture contained a pathogen known to cause bacteremia in this age group, bacteremia was coded. Of the 3,810 infants included in the analysis, a bacterial pathogen was identified in 38 children. The median total peripheral white blood cell count among infants with bacteremia was 13,900 cells per mm3, which was not significantly different from the count among infants without bacteremia.

The authors conclude that using a white blood cell count as the basis for the decision to obtain a blood culture probably will cause significant errors. Because of the potentially disastrous results of misdiagnosis, blood cultures should be obtained in all infants who are being evaluated for sepsis.

Continue Reading

More in AFP

Copyright © 2004 by the American Academy of Family Physicians.

This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP.  See permissions for copyright questions and/or permission requests.