Porcine FVIII Nijmegen Bethesda Assay
Use
This assay is used to quantitate the titer of FVIII-specific inhibitors to porcine FVIII concentrate.
Special Instructions
The porcine FVIII Nijmegen Bethesda assay has specific collection instructions that must be followed to ensure accurate results. Blood must be collected in a blue-top tube containing 3.2% buffered sodium citrate. Proper filling, immediate mixing, and appropriate collection sequence are critical. A discard tube is needed when using a winged collection system to avoid under-filling.
Limitations
Elevated levels of hemoglobin, bilirubin, or lipids can interfere with this assay. Certain anticoagulant drugs, such as direct thrombin inhibitors, direct Xa inhibitors, or heparin, can cause an erroneously low factor activity and falsely positive specific factor inhibitor results. Circulating anticoagulants like lupus anticoagulants may also impact results. It is important to avoid thawed samples and incorrect sample types, which are causes for rejection.
Methodology
Chromosomal / Cytogenetics (Nijmegen-modified Bethesda assay)
Biomarkers
LOINC Codes
- 3204-5
Result Turnaround Time
3-8 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1.5 mL
Minimum Volume
0.75 mL
Container
Blue-top (Sodium Citrate) tube
Collection Instructions
Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio. The sample should be mixed immediately by gentle inversion at least six times. If using a winged collection set, draw a discard tube first.
Patient Preparation
No special patient preparation is necessary.
Storage Instructions
Freeze
Causes for Rejection
Thawed sample, wrong sample type