Early diagnosis of gram-negative peritonitis in continuous ambulatory peritoneal dialysis patients with the Lymulus amebocyte lysate assay.

The treatment of peritonitis in continuous ambulatory peritoneal dialysis patients is empiric until the bacteriological results are available. The Lymulus amebocyte lysate assay (LAL) is a very sensitive method for the detection of endotoxin, a structural component of gram-negative bacteria. We performed the LAL assay in a prospective study in 36 consecutive episodes of peritonitis. The LAL assay was positive in all 10 episodes of gram-negative peritonitis (100% specificity). Treatment directed specifically against gram-negative or -positive infection was started based on the LAL assay result. In 26 episodes with LAL-negative test, a gram-positive bacterium was cultured in 23 episodes, in 1 there was fungal infection and 2 were sterile. In summary: the LAL assay is a rapid (1 h) and sensitive method for the differentiation of gram-positive or -negative peritonitis and enables starting an immediate and more appropriate antibiotic therapy.