Lack of Validity of Standard Corrections for White Blood Cell Counts of Blood-contaminated Cerebrospinal Fluid in Infants

Abstract

An evaluation of the validity in infants of standard computations for the correction of white cell counts in blood-contaminated cerebrospinal fluid (traumatic lumbar puncture) was undertaken. In 39 infants with significant blood contamination (>10⁴ red blood cells/μL) and no evidence of bacterial meningitis, both calculated corrections based on simultaneously obtained complete blood counts and estimated corrections based on average values resulted in overcorrection in a majority of cases (33 of 39 and 25 of 39, respectively). The mechanism of this overcorrection could not be defined. In eight infants with significant blood contamination and proven bacterial meningitis, correction computations normalized or overcorrectéd the white cell count in one case. It appears that standard computationis frequently overcorrect white cell counts in blood-contaminated cerebrospinal fluid and that the magnitude of the overcorrection may obsciire pathologic states in some cases.