Studies on a simple Limulus test, a slide method.

A simple micromethod of Limulus test was studied. Briefly, this method is as follows. A 20 microliter aliquot of Pregel lysate solution and the same amount of sample are dropped on the same place on the silicone coated slide glasg and mixed well. Then it is incubated at 37 degrees C for 30 minutes in a moisture chamber. After the incubation, the vibration of the droplet surface is observed. When the vibration is no longer observed, it is judged as positive reaction, and when the vibration is still observed as before the incubation, it is judged as negative reaction. Compared with the conventional tube method, this method has advantages as below: 1) the judgement of the result is relatively objective, 2) shorter incubation period is enough for the reaction to take place and 3) smaller amount of Limulus lysate is enough for each sample. Besides these merits, the detection limit of this method is not inferior to that of the tube method.