DRY UP METHOD AS A REVISED LIMULUS TEST WITH A NEW TECHNIQUE FOR GELATION INHIBITOR REMOVING

  • 1 January 1979
    • journal article
    • research article
    • Vol. 49  (1) , 19-25
Abstract
To detect endotoxins [etox], the Limulus test, especially its tube method, is used most widely. This method has shortcomings, e.g., the lack of objectivity on judgement, the necessity of long handling time and the requirement of relatively large amount of Limulus lysate. A new method was established. Sample and Limulus lysate are mixed on a silicone coated slide glass and incubated at 37.degree. C for 30 min, then heated to dry and observed. In samples which contain protein, the pre-treatments with (NH4)2SO4, dilution and boiling are performed to remove the gelation inhibitor. This method could be applied to such samples as physiological saline, plasma, urine, transudate, exudate, CSF and a suspension of Escherichia coli. This method has advantages in its objectivity because of the clear difference of the dry up patterns between positive reaction and negative, shortness of handling time (results can be obtained within 2 h from sampling), requirement of small amounts of sample and Limulus lysate (0.2 volume of sample and 0.1 volume of lysate are needed compared with the conventional method) and sensitivity (0.1 or 0.5 ng/ml of lipopolysaccharide (LPS)).