Affinity's Neutralization of ATIII - paired antibody set consists of Neutralizing antibody and Negative Control. The Principle of ATIII Neutralization - A polyclonal sheep antibody to human ATIII is added directly to human plasma and allowed to incubate for 20 minutes. During this time the antibody will bind to and inactivate (neutralize) the ability of ATIII to inhibit thrombin or activated factor X, even in the presence of heparin. Clot-based tests can then be performed on the neutralized sample. To control for the addition of antibody volume and buffer, a control antibody (non-immune sheep IgG, at the same concentration and in the same buffer) is added separately to aduplicate sample and the test is repeated.