UTILIZATION OF A CHROMOGENIC LIMULUS AMEBOCYTE LYSATE BLOOD ASSAY IN A MULTICENTER STUDY OF SEPSIS

We conducted a prospective study of a chromogenic LAL assay in 346 pat ients with sepsis syndrome, as defined by a modification of the Bone c riteria, and 131 healthy volunteers at eight member centers of the Aca demic Medical College Consortium (AMCC). We identified patients with e ndotoxemia (> 0.40 EU/ml) by measuring LAL-reactive material in whole blood, extracted by the Tamura nitric acid method, with the chromogeni c LAL (Pyrochrome(R)) assay. The mean result in sepsis patients with d etectable endotoxemia (n = 241) was 1.07 +/- 1.57 EU/ml, and the mean result in 131 volunteers was 0.151 +/- 0.113 EU/ml, with 73% of the vo lunteers' results falling below the detectable limit. The average inci dence of endotoxemia in sepsis patients was 33%, but varied 2.7-fold a mong the clinical centers (range 16-44%). Assay results were repeatabl e when samples tested frozen at the clinical sites were compared to re sults on frozen samples tested at Associates of Cape Cod, Inc. (ACC). Multiple samples were obtained from 40 patients at 18-24 h interval(s) . Fourteen multidraw patients (35%) were endotoxemic at one or more dr aw(s) and eight of these patients had two or more draws with endotoxin levels > 1.0 EU/ml. The presence of sulfa drugs gave false positive r esults in two patient samples. A positive LAL test did not correlate w ith culture-proven bacterial infection and did not significantly corre late with mortality. There was a correlation (P=0.014) between a patie nt having a positive LAL test and the presence of a fungal infection w hen mixed fungal and bacterial infections were included. There was no correlation with a positive LAL test when only a fungal infection was present (P=0.425) or when only a fungal and a Gram-positive infection was present (P=0.087).