Buffer system in an anti-thrombin III test
AssigneeOrtho Diagnostics, Inc.
InventorsStephen M. Autenrieth, Raymond P. Zolton
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Abstract
Disclosed is a procedure for conducting anti-thrombin III assays in which the conventional thrombin-anti-thrombin III treatment step is conducted at a pH of 7.9 to 8.5 maintained at the level by a buffer system comprising a buffering amount of N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid, N-2-hydroxyethylpiperazine-N'-3-propanesulfonic acid, N-tris-(hydroxymethyl)-methyl-2-amino-ethanesulfonic acid, N-tris-(hydroxymethyl)-methylglycine, or N,N-bis (2-hydroxymethyl)-glycine or a salt thereof. The compositions may also contain bacteriostatic agents.
Claims12
In the method for determining the anti-thrombin III level of an anti-thrombin III source which includes the steps of treating the source with thrombin whereby the thrombin is wholly or partially neutralized, treating the resulting mixtures with fibrinogen and measuring the clotting time of the fibrinogen treated mixture, the improvement which comprises conducting the thrombin-anti-thrombin III treatment step at a pH of between 7.9 to 8.5 maintained by a buffer system comprising a buffering amount of:
- N-2-hydroxyethylpiperazine-N'-2-ethane sulfonic acid, N-2-hydroxyethylpiperazine-N'-3-propane-sulfonic acid, N-tris-(hydroxymethyl)-methyl-2-amino-ethanesulfonic acid, N-tris-(hydroxymethyl)-methyl-glycine, or N,N-bis(2-hydroxymethyl)-glycine or a salt thereof.
In the method for determining the anti-thrombin III level of defibrinated serum or plasma which includes the steps of treating the serum or plasma with thrombin whereby the thrombin is wholly or partially neutralized, treating the resulting mixtures with fibrinogen and measuring the clotting time of the fibrinogen treated mixture, the improvement which comprises conducting the thrombin-anti-thrombin III treatment step at a pH of between 7.9 to 8.5 maintained by from three to nineteen parts per part of serum or plasma of an aqueous buffer system having a physiologic ionic strength and comprising a buffering amount of N-2-hydroxyethylpiperazine-N'-2-ethane sulfonic acid or a salt thereof and a base or acid sufficient in amount to maintain the pH of the system at 7.9 to 8.5 during the thrombin-anti-thrombin III treatment step.
In the method for determining the anti-thrombin III level of a defibrinated anti-thrombin III source which includes the steps of treating the source with thrombin whereby the thrombin is wholly or partially neutralized, treating the resulting mixtures with fibrinogen and measuring the clotting time of the fibrinogen treated mixture, the improvement which comprises conducting the thrombin-anti-thrombin III treatment step at a pH of between 7.9 to 8.5 maintained by from three to nineteen parts per part of source of a buffer system comprising a buffering amount of N-2-hydroxyethylpiperazine-N'-2-ethane sulfonic acid or N-tris-(hydroxymethyl)-methyl-2-aminoethane sulfonic acid, or a salt thereof.
Dependencies are inferred from the claim text.