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New Lab Test Screens for Inhibitors in Patients Receiving Hemlibra®

August 20, 2019
New Lab Test Screens for Inhibitors in Patients Receiving Hemlibra®

A new test has become available to screen for factor VIII (FVIII) inhibitors in patients with hemophilia A who are receiving Hemlibra® therapy.

Validated by LabCorp’s specialty laboratory, Colorado Coagulation, - the Factor VIII Chromogenic Bethesda Inhibitor Profile is a blood test that measures the titer (the amount of inhibitor present) of FVIII antibodies in patients receiving Hemlibra. The amount of inhibitor antibodies present in the blood (titer), are reported in Chromogenic Bethesda units (CBU). Patients with an inhibitor titer below 5 CBU are said to have a weak, low-titer inhibitor, while those with a titer of 5 or more CBU have a potent, high-titer inhibitor.

In the fall of 2017, Hemlibra was approved by the U.S. Food and Drug Administration (FDA) for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adults and children with hemophilia A with FVIII inhibitors. The following year, Hemlibra received expanded FDA approval for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adults and children, ages newborn and older with hemophilia A without FVIII inhibitors.

The test was developed in lieu of using a standard clot-based FVIII test system which cannot accurately determine inhibitor titer levels because of interference of Hemlibra in the clot-based FVIII activity assay. The Factor VIII Chromogenic Bethesda Inhibitor Profile is designed to accurately measure endogenous FVIII activity and inhibitor titers by utilizing - a bovine (cow) based FVIII chromogenic assay. Bovine components, which are insensitive to Hemlibra, allow for more accurate detection and quantification of FVIII inhibitors in the presence of Hemlibra.

If you are a patient and wish to submit question/comments please visit the Labcorp Patient Inquiry page.

If you are a healthcare provider and wish to submit questions/comments visit Labcorp Provider Inquiry page.

The test number for the Factor VIII Chromogenic Bethesda Inhibitor Profile is 504722.