Concordance of endotoxemia with gram-negative bacteremia in patients with gram-negative sepsis: a meta-analysis.

The Limulus amebocyte lysate (LAL) assay is a sensitive method for detecting endotoxin. Using gram-negative (GN) bacteremia as the basis for comparison, concordance with endotoxemia in 45 studies could be expressed as an odds ratio. Calculation of summary odds ratios by the Mantel-Haenszel-Peto method indicated that the concordance of the results was no higher by the chromogenic LAL assay than by the gelation version, and the sensitivity was improved by only 11% (62 versus 51%). Endotoxemia was detected in 77 (68%) of 114 patients with bacteremia caused by an organism that was not a member of the family Enterobacteriaceae, whereas endotoxemia was detected in only 120 (45%) of 269 patients with bacteremia caused by a member of the family Enterobacteriaceae or an anaerobe (P < 0.001). This difference was also apparent for patients with GN bacteremia for whom a fatal outcome had been recorded. The prevalence of GN bacteremia in the tested population and the type of etiological agent are critical and previously unrecognized variables which affect the interpretation of the LAL test in patients with suspected sepsis.