Comparison of the pyrogen tests in rabbits and with limulus lysate.

In the past years an assortment of samples of plasma proteins, enzymes, vaccines and blood substitutes were tested comparatively in rabbits (pyrogen test, European Pharmacopoeia) and with the LAL test (Pyrogent, Byk-Mallinckrodt, Inc.). Specificity and sensitivity were tested with endotoxins and lipid A of gram-negative bacteria. The limulus amebocyte lysate (LAL) test gave similar results or was tenfold more sensitive than the assay in rabbits. More than 300 samples of drugs were examined by both tests. All preparations positive in the rabbit test were positive in the LAL test too. In the testing of plasma proteins the LAL test was more sensitive. The examination of 45 samples of vaccines for pyrogens gave the same result in both assays. Streptokinase does not inhibit the LAL test unspecifically. The LAL test is not an alternative but an additional method in the detection of lipopolysaccharides in drugs.