Bethesda Titer
11 days
The factor XII inhibitor (Bethesda titer) assay is performed using an activated partial thromboplastin time (aPTT)-based system.6 Serial dilutions are made of patient plasma with veronal buffered saline, then mixed with normal plasma containing close to 100% factor XII activity, and are then incubated for two hours. An aPTT-based factor XII assay using factor XII-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 XII inhibitor that neutralized 0.5 IU of factor XII 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 XII activity, factor XII Bethesda titer
Accredited Laboratory Partner
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Detects inhibitors to Factor XII. Used in acquired bleeding disorders or unexplained aPTT elevation.
Plasma
6 mL (2 mL in each of 3 tubes)
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 |
Bethesda Titer
11 days
The factor XII inhibitor (Bethesda titer) assay is performed using an activated partial thromboplastin time (aPTT)-based system.6 Serial dilutions are made of patient plasma with veronal buffered saline, then mixed with normal plasma containing close to 100% factor XII activity, and are then incubated for two hours. An aPTT-based factor XII assay using factor XII-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 XII inhibitor that neutralized 0.5 IU of factor XII 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 XII activity, factor XII Bethesda titer
Accredited Laboratory Partner
Contact Technical Support
Detects inhibitors to Factor XII. Used in acquired bleeding disorders or unexplained aPTT elevation.
Plasma
6 mL (2 mL in each of 3 tubes)
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 |