Effect of the white blood count on the clinical management of the febrile infant

Abstract

Background: The white blood count is commonly used in the evaluation of the febrile infant without a focal source of infection. This study describes the physician's use of diagnostic tests in this clinical situation and also evaluates the effect of an elevated white blood count (WBC) on diagnostic test ordering and patient management.

Methods: A case scenario describing a febrile infant was mailed to all 294 pediatric, family, general, and emergency physician members of the Academy of Medicine of Cleveland. Questions about test ordering and case management were asked, both before and after the patient's WBC was known. Physicians were randomly assigned to receive a case scenario with either a normal or an elevated WBC.

Results: Of the 294 physicians contracted, 196 (67%) returned usable questionnaires. Physicians ordered an average of 1.4 tests in the initial management of the case, for an average cost of $82. Emergency physicians ordered more tests than other physicians (2.4 vs 1.2 tests, P = .001). Once the WBC was known, physicians in the high WBC group ordered more additional tests than the normal WBC group (0.89 vs 0.33 tests, P less than .001), and were more likely to change to a more aggressive therapeutic management strategy (P less than .001).

Conclusions: The cost of physician-ordered laboratory testing is significant for the clinical scenario of a febrile infant without a localizing source. An elevated WBC affects physician management by causing more tests to be ordered and by influencing some physicians to choose more aggressive management strategies.