Evaluation of an endotoxin-specific limulus amebocyte lysate assay using leukocyte-rich plasma for the diagnosis of gram-negative bacterial infection

Clinical relevance of leukocyte-associated endotoxins measured by semi-automatic synthetic luminescent substrate method

“…From these points, we believe that SALS has sufficient potential for clinical application in the future. The method of using LRP instead of plasma as the target of endotoxin measurement has already been reported by Kan et al 14 , and a method of collecting LRP at 37 °C using dextran as an aggregating agent has recently been devised by us (LRP37 method) 10 . Samples obtained by this method were used for measurement of this study.The method to obtain LRP uses the aggregating agent dextran under 1 × g conditions to remove erythrocytes which interfere the limulus test, and leukocytes are still suspended in plasma.…”

A Dextran-Based Warming Method for Preparing Leukocyte-Rich Plasma and its Clinical Application for Endotoxin Assay

“…The sensitivity and specificity of techniques for diagnosing sepsis using conventional plasma endotoxin assays are too low, and plasma endotoxins are not detectable in many cases of gram-negative bacterial infection [1]. Kan et al demonstrated that LRP is useful for the diagnosis of endotoxemia and found a clear improvement in the sensitivity and specificity of this assay compared with the plasma method [1,6]. Their experiments were performed with a commercially available HES solution, which is used as a cryopreservation agent for cultured cells.…”

“…Yaegashi et al [5] measured endotoxin levels in the white blood cell fraction (buffy coat) and reported the detection of endotoxins in this fraction, but not in the plasma, for some specimens. Kan et al [1] reported that even if the endotoxin levels were below the detection limit for the plasma method, LRP endotoxin levels could be measured in some specimens from patients with sepsis. Similar unexplainable results were also obtained in this study in approximately 8% of cases.…”

“…In Japan, the standard practice for measuring blood endotoxin concentrations is an endotoxin-specific limulus amebocyte lysate (LAL) assay using platelet-rich plasma (PRP). However, the sensitivity of this assay is too low to be considered diagnostically efficient [1].…”

“…However, this method is too complicated and impractical for routine use. Therefore, we attempted to use leukocyte-rich plasma (LRP) for the endotoxin assay [1,6] and found once again that the measurement of leukocyte-bound endotoxins was necessary. Separation of LRP was previously performed by adding the hemagglutinating agent hydroxyethyl starch (HES) to the blood [7,8].…”