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Gram negative bacteria screening method with horseshoe crab amebocyte lysate (LAL)

  • US 4,717,658 A
  • Filed: 12/03/1985
  • Issued: 01/05/1988
  • Est. Priority Date: 12/03/1985
  • Status: Expired due to Fees
First Claim
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1. A gram negative bacteria screening method for determining the presence of at least 104 gram negative bacteria cells per milliliter of a urine sample, comprising the steps of:

  • (a) adding an undiluted urine sample to be tested to a test tube containing horseshoe crab amebocyte lysate and a first buffer capable of resisting a pH change in the pH range of from about 6.3 to about 7.5, to form a test tube mixture wherein the concentration of lysate is at least 3.5 milligrams per milliliter of the test tube mixture formed;

    (b) incubating the test tube mixture for a time sufficient to activate the lysate;

    (c) contacting a test device with the activated test tube mixture, said test device comprising a carrier matrix incorporated with a synthetic peptide substrate containing a chromogenic or fluorogenic leaving group capable of being cleaved by the activated lysate and a second buffer capable of resisting pH change in the pH range of from about 8.0 to about 8.9;

    (d) removing the contacted test device; and

    (e) determining the concentration of cleaved leaving group.

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