Bethesda Titer
7 days
The factor VIII inhibitor (Bethesda titer) assay is performed using an activated partial thromboplastin time (aPTT)-based test system.6 Serial dilutions are made of patient plasma with veronal buffered saline, then mixed with normal plasma containing close to 100% factor VIII activity and are then incubated for one hour. An aPTT-based factor VIII assay using factor VIII-depleted plasma substrate is then performed on these incubated mixtures. Results are compared to those of incubated normal plasma. One Bethesda unit is defined as the amount of factor VIII inhibitor that neutralized 0.5 IU of factor VIII in this system. The number of serial dilutions tested is based on the anticipated level of the inhibitor.
Test Includes: Activated partial thromboplastin time (aPTT), aPTT 1:1 mix with normal plasma, aPTT 1:1 incubated mix with normal plasma, aPTT 1:1 mix with saline, factor VIII activity, factor VIII Bethesda titer
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Comprehensive evaluation for Factor VIII inhibitors, including titer and response. Used in advanced Hemophilia A cases.
Plasma
3 mL
Blue top (sodium citrate) tube
No special preparation is required for this test. You may eat, drink, and take your medications as normal, unless instructed otherwise by your healthcare provider.
Citrated Plasma samples should be collected by double centrifugation
| Temperature | Period |
|---|---|
| Frozen | Contact Technical Support |