Which statement best describes the Bethesda assay?

Which statement best describes the Bethesda assay?

• A. Measures thrombin generation
• B. Quantifies inhibitors against a coagulation factor
• C. Assesses platelet function via ristocetin
• D. Determines fibrinogen level

Answer: (B)

The Bethesda assay is designed to quantify inhibitors against a coagulation factor, most commonly factor VIII. In the test, patient plasma is mixed with normal pooled plasma and incubated at 37°C. If inhibitors are present, they neutralize the factor VIII in the normal plasma, so the residual activity is reduced. After incubation, the remaining factor VIII activity is measured, and the inhibitor strength is reported in Bethesda units per milliliter. One Bethesda unit is defined as the amount of inhibitor that reduces factor VIII activity by 50% under the assay conditions. This assay specifically identifies and measures inhibitors, which is essential for managing conditions like hemophilia A with suspected factor VIII inhibitors. It does not assess thrombin generation, platelet function via ristocetin, or fibrinogen levels, which are determined by other tests.

The Bethesda assay is designed to quantify inhibitors against a coagulation factor, most commonly factor VIII. In the test, patient plasma is mixed with normal pooled plasma and incubated at 37°C. If inhibitors are present, they neutralize the factor VIII in the normal plasma, so the residual activity is reduced. After incubation, the remaining factor VIII activity is measured, and the inhibitor strength is reported in Bethesda units per milliliter. One Bethesda unit is defined as the amount of inhibitor that reduces factor VIII activity by 50% under the assay conditions. This assay specifically identifies and measures inhibitors, which is essential for managing conditions like hemophilia A with suspected factor VIII inhibitors. It does not assess thrombin generation, platelet function via ristocetin, or fibrinogen levels, which are determined by other tests.